diff --git a/README.md b/README.md
index 87857b1..ccc0d36 100644
--- a/README.md
+++ b/README.md
@@ -13,7 +13,12 @@ Exploration a Rust Programming Language - (33 concepts)
 
 ## TYPES
 
-// Todo
+1. [Struct](./Rust_Concepts/src/struct.rs)
+2. [Enum](./Rust_Concepts/src/enum.rs)
+3. Option         // TODO 
+4. Result (later)
+5. Vec (later)
+6. HashMap (later)
 
 ## CONTROL
 
diff --git a/Rust_Concepts/Cargo.toml b/Rust_Concepts/Cargo.toml
index 3e6ad26..c1c42ce 100644
--- a/Rust_Concepts/Cargo.toml
+++ b/Rust_Concepts/Cargo.toml
@@ -34,4 +34,15 @@ path = "src/clone.rs"   # path to the source file
 [[bin]]
 name = "StackVSHeap"          # the name you’ll use with --bin
 path = "src/stack_vs_heap.rs"   # path to the source file
-# cargo run --bin StackVSHeap
\ No newline at end of file
+# cargo run --bin StackVSHeap
+
+[[bin]]
+name = "Struct"          # the name you’ll use with --bin
+path = "src/struct.rs"   # path to the source file
+# cargo run --bin Struct
+
+
+[[bin]]
+name = "Enum"          # the name you’ll use with --bin
+path = "src/enum.rs"   # path to the source file
+# cargo run --bin Enum
\ No newline at end of file
diff --git a/Rust_Concepts/src/enum.rs b/Rust_Concepts/src/enum.rs
new file mode 100644
index 0000000..b7e4d08
--- /dev/null
+++ b/Rust_Concepts/src/enum.rs
@@ -0,0 +1,365 @@
+/* Rust Concepts: https://sociocyber.site/rust_concepts_v2.html
+   Concept: Enum (Lives in Stack)
+   
+   Usage: Create a Type with named variants. Match this for control flow, That variants optionaly can carry data.  
+   P.S. "Variant" means just a text name, like "Red", "Green", "Yellow", "Ok", "Something", "Ball", "Earth",.  
+
+   Description:
+
+   enum Name {
+      Variant1, 
+      Variant2,
+      Variant3(type) <- data types: i32, u32, String and etc,.
+   }
+
+   let some = Name::Variant1
+*/
+
+#[derive(Debug)]
+#[allow(dead_code)] // - ingore all warings about unused enum fields
+enum Apple {
+   Red(String),        
+   Yellow,          // warning: variants `Red` and `Yellow` are never constructed  
+   Green,
+}
+
+
+#[derive(Debug)]
+#[allow(dead_code)]
+enum GnuLinux {
+   Arch,
+   Kali,
+   Debian,
+   Trisquel,
+   Guix,
+   Windows(Release)
+}
+
+#[derive(Debug)]
+#[allow(dead_code)] // - ingore all warings about unused enum fields
+enum Release {
+   // _Eleven, // '_' means this field not used, or add #[allow(dead_code)] derictive
+   Ten,
+   Seven
+}
+
+#[derive(Debug)]
+#[allow(dead_code)]
+enum Partion {
+   Root,
+   Home,
+   Hard(u8), // Hard(1), Hard(2),. 
+}   
+
+#[derive(Debug)]
+#[allow(dead_code)]
+enum Signal {
+    Red,          
+    Yellow,      
+    Green(u32), // carries seconds remaining; index = (2)
+}
+
+#[derive(Debug)]
+#[allow(dead_code)]
+enum NetworkStatus {
+   NotFound = 404,
+   Ok = 200,
+   Forbiden = 500
+}
+
+fn main() {
+   // Create enum type
+   let apple1 = Apple::Green; 
+   println!("I eating an apple with color {:?}", apple1);
+
+   /*
+
+   STACK
+   ┌─────────────────────────────┐
+   │  apple1                     │
+   │  ┌───────────────────────┐  │
+   │  │ Tag: Green (variant)  │  │
+   │  │ (discriminant = 2)    │  │
+   │  └───────────────────────┘  │
+   │  Size: 1 byte (depends on   │
+   │        number of variants)  │
+   └─────────────────────────────┘
+
+   HEAP
+   (unused - enums are stack-allocated)
+   */
+
+
+
+
+   // Create enum type with heap-data
+   let apple2 = Apple::Red( String::from("Fuji") ); // Fuji - saved in HEAP
+   println!("I eating an apple with color {:?}", apple2);
+
+   /*
+
+   STACK
+   ┌──────────────────────┐
+   │  apple1              │
+   │  ┌────────────────┐  │
+   │  │ Tag: Red (0)   │  │
+   │  │ ptr: 0x1000 ───────────┐
+   │  │ len: 4         │  │    │
+   │  │ capacity: 4    │  │    │
+   │  └────────────────┘  │    │
+   └──────────────────────┘    │
+                               │
+                               ▼
+   HEAP (Memory Address 0x1000)
+   ┌──────────────────────────────┐
+   │  [F][u][j][i]                │
+   │  0x1000                      │
+   │  (4 bytes allocated)         │
+   │  (capacity: 4 bytes)         │
+   └──────────────────────────────┘
+
+   */
+
+
+   let signal = Signal::Green(200);
+   describe(signal);
+
+   /*
+
+   STACK
+   ┌────────────────────────────────┐
+   │  signal                        │
+   │  ┌──────────────────────────┐  │
+   │  │ Tag: Green (2)           │  │  (2) - means variant[index]
+   │  │ Data: 200 (u32)          │  │
+   │  │ (4 bytes)                │  │
+   │  └──────────────────────────┘  │
+   └────────────────────────────────┘
+
+   HEAP
+   (unused - no heap allocation needed)
+
+   */
+
+
+
+
+   let status = NetworkStatus::Ok;
+   println!("Network status: {}", status as i32); // Recommendation for typed values like i32,. Still use Struct instead of Enum. 
+
+
+   let my_operating_system = GnuLinux::Arch;                     // Arch Linux, we call new stack frame as "my_operating_system", We save a Tag (This Enum Type saved in STACK Frame as Tag: "Enum Name", with additional fields: len,. ),  
+   // let my_operating_system = GnuLinux::Windows(Release::Ten); // windows 10
+   
+   // Just call functions and todo something, as use can see with enums code can be simple to read.  
+   // P.S. '&' in '&variable' to indicate of the variable is a reference = read a value (Enum Type in this case), without holding it.
+   describe_os(&my_operating_system); // share Tag
+   install_base_packagers(&my_operating_system); // share Tag
+
+   format_disk(Partion::Root); // Create here and Share Tag  (not variable defined for enum type)
+   format_disk(Partion::Home);
+   format_disk(Partion::Hard(1)); //  Create here and Share Tag + number in here number saved in STACK, NOT in HEAP
+   format_disk(Partion::Hard(2));
+
+   install_base_packagers(&GnuLinux::Kali);
+   install_base_packagers(&GnuLinux::Trisquel);
+}
+
+
+
+
+
+
+// Functions - not worry about  "match",. we'll explore control flow in later lessons 
+fn describe(s: Signal) {
+    match s {
+        Signal::Red       => println!("Stop!"),
+        Signal::Yellow    => println!("Slow down"),
+        Signal::Green(n)  => println!("Go! {}s left", n),
+    }
+}
+
+fn format_disk(part: Partion) {
+   println!("Formating as ext4: {:?}", part);
+}
+
+fn install_base_packagers(os: &GnuLinux) {
+   println!("Install for {:?}", &os);
+
+   match os {
+      GnuLinux::Arch => {
+         println!("pacman -Syu wayland blender krita")
+      },
+      GnuLinux::Kali | GnuLinux::Debian | GnuLinux::Trisquel => {
+         println!("apt update -y && apt upgrade -y xorg kicad arduinoide")
+      },
+      _ => println!("Noting")
+   }
+}
+
+fn describe_os(os: &GnuLinux) {
+   match os {
+      GnuLinux::Arch => println!("I use Arch btw!"),
+      GnuLinux::Kali => println!("Yea i can hack you computer"),
+      GnuLinux::Debian => println!("Super stable, good choice!"),
+      GnuLinux::Trisquel => println!("GNU/Linux, easy-peasy, interface like windows, no terminals, without linux kernel BLOBS, only libre software!"),
+      GnuLinux::Guix => println!("GNU/Linux! Guix! Not easy for beggener, but.. Not systemd, not blobs, custom system config, sheme language for describe what packages you want install.,"),
+      _ => println!("Oh! Damn! You are use a Windows? Oh no.. crap. Now you can trash you computer OR.. re-install your OS.")
+   }
+}
+
+
+
+// More examples of enums
+
+// enum Protocol {
+//    Tcp, 
+//    Udp,
+//    Http,
+//    Https,
+//    Dns,
+//    Ftp,
+//    Ssh,
+// }
+
+// #[derive(Debug)]
+// enum Planets {
+//    Earth_Water, // Eeath, but you know,. oceans so much more than earth _/(00)\_
+//    Moon,
+//    Other
+// }
+
+// enum DataCollector {
+//    Sensors,
+//    Production,
+//    Resources
+// }
+
+// enum DataBase {
+//    Redis,
+//    SQLite,
+//    PostgreSQL
+// }
+
+// enum Data {
+//    SensorData,
+//    ProductionData,
+//    ResourceData(Resource), // takes Resource enum
+// }
+
+
+// enum Resource {
+//     // Metals and Metallic Elements
+//     Metal(String),
+    
+//     // Precious and Semi-Precious Stones
+//     PreciousStone(String),
+    
+//     // Rare Earth Elements
+//     RareEarthElement(String),
+    
+//     // Fossil Fuels
+//     FossilFuel(String),
+    
+//     // Nuclear and Radioactive Materials
+//     RadioactiveMaterial(String),
+    
+//     // Non-metallic Minerals
+//     Mineral(String),
+    
+//     // Gases
+//     Gas(String),
+    
+//     // Liquids
+//     Liquid(String),
+    
+//     // Soil and Earth Materials
+//     Soil(String),
+    
+//     // Organic Materials (Non-Food)
+//     OrganicMaterial(String),
+    
+//     // FOOD RESOURCES - Generic Categories
+//     Grain(String),
+//     Vegetable(String),
+//     Fruit(String),
+//     Protein(String),
+//     Dairy(String),
+//     Oil(String),
+//     Spice(String),
+//     Herb(String),
+//     Legume(String),
+//     NutOrSeed(String),
+//     Fungus(String),
+//     Algae(String),
+//     Sweetener(String),
+//     Beverage(String),
+// }
+
+// enum ResourceHubApi {
+//    Url(String),
+// }
+
+// enum Status {
+//    Online,
+//    Loading,
+//    ErrorCode(u16),
+// }
+
+// enum System {
+//    SystemOnline, // means it's OK
+//    SystemError,
+//    SystemMessage(String),
+// }
+
+// enum VoiceMessage {
+//    Greeting,
+//    Alert,
+//    Notifycation,
+//    Time,
+//    TimeReminder,
+//    TaskStart,
+//    TaskEnd,
+//    Instruction,
+// }
+
+// enum Phone {
+//    Model(String)
+// }
+
+
+// Window
+   // MainView
+   // SideBar
+      // Topic1
+      // SubMenu
+         // Item1
+         // Item2
+      // Topic2
+      // SubMenu
+         // Item1
+         // Item2
+
+// enum Window {
+//    MainView,
+//    SideBar(SideBar),
+//    DataBar,
+//    StatusBar,
+//    StatusLine
+// }
+
+// enum SideBar {
+//    Topic(String, SubMenu),
+// }
+
+// enum SubMenu {
+//    Item(ItemData)
+// }
+
+// enum ItemData {
+//    Title,
+//    Description,
+//    PreviewUrls(Vec<String>),
+//    VideoUrls(Vec<String>),
+//    BooksUrls(Vec<String>),
+// }
\ No newline at end of file
diff --git a/Rust_Concepts/src/main.rs b/Rust_Concepts/src/main.rs
index d66f458..a773f28 100644
--- a/Rust_Concepts/src/main.rs
+++ b/Rust_Concepts/src/main.rs
@@ -1,3 +1,14 @@
+/* Rust Concepts: https://sociocyber.site/rust_concepts_v2.html
+   Concept:  
+   
+   Usage:
+   
+   Description:
+
+   Stack/Heap shemes
+*/
+
+
 fn main() {
 	// to run examples use
 	// cargo run --bin [Something]
diff --git a/Rust_Concepts/src/struct.rs b/Rust_Concepts/src/struct.rs
new file mode 100644
index 0000000..27f7477
--- /dev/null
+++ b/Rust_Concepts/src/struct.rs
@@ -0,0 +1,224 @@
+/* Rust Concepts: https://sociocyber.site/rust_concepts_v2.html
+   Concept: Struct 
+   Usage: Create new Data Type;
+
+
+   What struct means?
+   Group of data types, with one name.( Save data in one thing,. )
+   
+   stuct Name {       
+      field1: Type, (i32, u32, String, &[], ...)
+      field2: Type,
+      field3: Type,
+      field4: Type,
+   }
+
+   
+   * Use String::from() for clarity (more common in structs) [Fast]
+   * Not use .to_string() for structs.
+   ** Use .to_string()  when converting other types only: let number = "134".to_string()
+
+   P.S. '_' in '_variable' means = hide compiler warnings: unused variable
+
+   * later in lessons -> add methods for struct's data, add implimentation, constructor, impl traits, tuple structs, unit structs (no fields, used for traits)
+     nested structs, with generics, builder pattern 
+*/
+
+#[derive(Debug)] // Don't worry about this compiler-derictive, In later lessons we'll explore what this means.
+struct Book {
+   name: String,
+   count: u32,
+   price: u32,
+}
+
+fn main() {
+   // How create?
+   let harry_poter = Book {
+      // name: "Harry Poter".to_string(), // not use .to_string() in structs can be slow! 
+      name: String::from("Harry Poter"),
+      count: 10,
+      price: 200,
+   };
+
+   /*
+
+   STACK (and his frames) [CPU]                    HEAP     [MEM]
+   ─────────────────────────────────────           ──────────────────────────
+   frame: main()                                   ┌────────────────────────┐
+   ┌───────────────────────────────────┐           │ "Harry Poter"          │
+   │ harry_potter : Book               │           │ 12 bytes, UTF-8        │
+   │ ┌─────────────────────────────┐   │           │ [H][a][r][r][y][ ]...  │
+   │ │ name : String               │   │  owns     │ [P][o][t][e][r]        │
+   │ │ ┌─────────────────────────┐ │   │ ────────► │                        │
+   │ │ │ ptr                     │ │   │           │ dropped when           │
+   │ │ │ len = 12                │ │   │           │ Book drops             │
+   │ │ │ cap = 12                │ │   │           └────────────────────────┘
+   │ │ │ [ 3 × usize on stack ]  │ │   │
+   │ │ └─────────────────────────┘ │   │
+   │ └─────────────────────────────┘   │
+   │                                   │
+   │ ┌─────────────────────────────┐   │
+   │ │ count : u32 = 10            │   │           (no heap — u32 fits
+   │ └─────────────────────────────┘   │            directly on stack)
+   │                                   │
+   │ ┌─────────────────────────────┐   │
+   │ │ price : u32 = 200           │   │
+   │ └─────────────────────────────┘   │
+   └───────────────────────────────────┘
+
+   STACK — frame: main()
+   ───────────────────────────────────────────────
+   address   field            bytes
+   ───────────────────────────────────────────────
+   0x00      name.ptr         8  (pointer to heap)
+   0x08      name.len         8
+   0x10      name.cap         8
+   0x18      count            4  (u32)
+   0x1C      price            4  (u32)
+   ───────────────────────────────────────────────
+                       total: 32 bytes
+
+   */
+
+
+   let one_in_space = Book {
+      name: String::from("Disteller: One in Space"),
+      count: 1,
+      price: 250,
+   };
+   // let books_in_shop: [Book; 2] = [Book{name: "Harry Poter".to_string(), count: 1, price: 200}, Book{name: "s".to_string(), count: 2, price: 300}];
+
+   // What if i need change a variables in struct when saved in array?
+   // Make array mutable ( add "mut" ) 
+   let mut books_in_shop: [Book; 2] = [harry_poter, one_in_space];
+
+   /*
+   STACK (and his frames) [CPU]                         HEAP     [MEM]
+   ──────────────────────────────────────────           ──────────────────────────
+   frame: main()
+   ┌──────────────────────────────────────┐
+   │ books_in_shop : [Book; 2]            │
+   │                                      │
+   │ [0] harry_potter                     │
+   │ ┌────────────────────────────────┐   │             ┌────────────────────────┐
+   │ │ name : String                  │   │             │ "Harry Poter"          │
+   │ │ ┌──────────────────────────┐   │   │   owns      │ 12 bytes, UTF-8        │
+   │ │ │ ptr                      │   │   │ ──────────► │ [H][a][r][r][y][ ]...  │
+   │ │ │ len = 12                 │   │   │             │ [P][o][t][e][r]        │
+   │ │ │ cap = 12                 │   │   │             └────────────────────────┘
+   │ │ └──────────────────────────┘   │   │
+   │ └────────────────────────────────┘   │
+   │ ┌────────────────────────────────┐   │             (separate heap alloc)
+   │ │ count : u32  =  10             │   │
+   │ └────────────────────────────────┘   │
+   │ ┌────────────────────────────────┐   │
+   │ │ price : u32  =  200            │   │
+   │ └────────────────────────────────┘   │
+   │                                      │
+   │ [1] one_in_space                     │
+   │ ┌────────────────────────────────┐   │             ┌────────────────────────┐
+   │ │ name : String                  │   │             │ "One in Space"         │
+   │ │ ┌──────────────────────────┐   │   │   owns      │ 12 bytes, UTF-8        │
+   │ │ │ ptr                      │   │   │ ──────────► │ [O][n][e][ ][i][n]...  │
+   │ │ │ len = 12                 │   │   │             │ [S][p][a][c][e]        │
+   │ │ │ cap = 12                 │   │   │             └────────────────────────┘
+   │ │ └──────────────────────────┘   │   │
+   │ └────────────────────────────────┘   │
+   │ ┌────────────────────────────────┐   │
+   │ │ count : u32  =  1              │   │
+   │ └────────────────────────────────┘   │
+   │ ┌────────────────────────────────┐   │
+   │ │ price : u32  =  999            │   │
+   │ └────────────────────────────────┘   │
+   │                                      │
+   │  [Book; 2] = 64 bytes flat on stack  │
+   │  2 separate heap allocs for String   │
+   └──────────────────────────────────────┘
+
+
+
+   STACK — frame: main()
+   ─────────────────────────────────────────────────
+   address      field                    bytes
+   ─────────────────────────────────────────────────
+   rbp - 64     books_in_shop[0].name.ptr    8
+   rbp - 56     books_in_shop[0].name.len    8
+   rbp - 48     books_in_shop[0].name.cap    8
+   rbp - 40     books_in_shop[0].count       4
+   rbp - 36     books_in_shop[0].price       4
+   ─────────────────────────────────────────────────
+   rbp - 32     books_in_shop[1].name.ptr    8
+   rbp - 24     books_in_shop[1].name.len    8
+   rbp - 16     books_in_shop[1].name.cap    8
+   rbp - 8      books_in_shop[1].count       4
+   rbp - 4      books_in_shop[1].price       4
+   ─────────────────────────────────────────────────
+                                 total: 64 bytes
+
+
+   what is max STACK size?
+   
+   Depends on OS and how the thread was created.
+
+   OS / context                default stack size
+   ──────────────────────────────────────────────
+   Linux                       8 MB
+   Windows                     1 MB
+   macOS                       8 MB  (main thread)
+                               512 KB (other threads)
+   ──────────────────────────────────────────────
+   Rust main thread            inherits OS default
+   Rust spawned thread         2 MB   (Rust sets this)
+   embedded / no_std           you set it manually
+                               often 4–64 KB
+   ──────────────────────────────────────────────
+
+   If you exceed it → stack overflow → program crashes.
+   
+   let big: [u8; 10_000_000] = [0; 10_000_000];  // 10 MB → boom
+   
+   
+   // fix — put it on heap
+   let big: Vec<u8> = vec![0; 10_000_000];        // ok, all data saved in HEAP [MEM], in STACK save only pointer to data
+
+
+   You can change stack size for spawned threads:
+   std::thread::Builder::new()
+    .stack_size(16 * 1024 * 1024)  // 16 MB
+    .spawn(|| { ... });
+
+   */
+
+   // How print?
+   println!("Book: {}", books_in_shop[0].name);
+   println!("Count: {}", books_in_shop[0].count);
+   println!("Price: {}", books_in_shop[0].price);
+   println!("------------------");
+   println!("Book: {}", books_in_shop[1].name);
+   println!("Count: {}", books_in_shop[1].count);
+   println!("Price: {}", books_in_shop[1].price);
+
+   println!("------------------");
+   println!("UPDATE");
+
+   // How chage fields (variables) in struct?
+   books_in_shop[0].name = String::from("Genry Proper");
+   books_in_shop[0].count = 3000;
+   books_in_shop[0].price = 50;
+
+   println!("Book: {}", books_in_shop[0].name);
+   println!("Count: {}", books_in_shop[0].count);
+   println!("Price: {}", books_in_shop[0].price);
+
+
+   // What if i need change a variables in struct (when struct not in array)? 
+   // Make struct mutable.
+   // Add "mut"
+   let mut mutable_book = Book {
+      name: String::from("Harry You are."),
+      count: 1,
+      price: 250,
+   };
+   mutable_book.name = String::from("Genry Potato");
+   println!("Mutable Book: {}", mutable_book.name);
+}
\ No newline at end of file