docs: update readme

Author: sijanthapa171

.github/README.md

@@ -1,34 +1,130 @@
-## 🚀 Installation
 
-### Quick Start
+## Installation
 
-1. **Clone the Repository**
-   ```bash
-   git clone https://github.com/sijanthapa171/NixOS.git
-   cd NixOS
-   ```
+> [!Note]
+> Before proceeding with the installation, check these files and adjust them for your system:
+>
+> - `hosts/Default/variables.nix`: Contains host-specific variables.
+> - `hosts/Default/host-packages.nix`: Lists installed packages for the host.
+> - `hosts/Default/configuration.nix`: Module imports for the host and extra configuration.
 
-2. **Review Configuration**
-   ```bash
-   # Edit flake.nix to set your preferences
-   nvim flake.nix
-   ```
+<!-- You can install this configuration either on a running system or from the NixOS live installer. The minimal ISO is recommended and can be downloaded from the [official NixOS website](https://nixos.org/download/#nixos-iso). -->
 
-3. **Installation Options**
+You can install on a running system or from the NixOS live installer. Get the minimal ISO from the [NixOS website](https://nixos.org/download/#nixos-iso).
 
-   For existing NixOS systems:
-   ```bash
-   ./install.sh
-   ```
+### Installation Steps
 
-   For fresh installations:
-   ```bash
-   ./live-install.sh
-   ```
+1. Clone the Repository:
+
+```bash
+git clone https://github.com/sijanthapa171/NixOS.git ~/NixOS
+```
+
+<!-- 2. Navigate to the Directory: -->
+
+2. Change Directory:
+
+```bash
+cd ~/NixOS
+```
+
+3. Run the Installer:
+
+```bash
+./install.sh
+```
+
+<!-- The script handles host setup, username configuration, and automatically generates `hardware-configuration.nix` based on your hardware. -->
 
-4. **Post-Installation**
-   ```bash
-   # Rebuild and switch to the new configuration
-   sysup
+The install and rebuild scripts automate the setup process, including hosts, username, and applying the configuration. It also automatically generates the hardware-configuration.nix file based on your system's detected hardware, eliminating the need to manually generate it.
+
+## Usage
+
+### Managing Hosts
+
+**Method 1: Automatic** - run the installer again to select or create another host:
+
+```bash
+./install.sh
+```
+
+**Method 2: Manual:**
+
+1. Copy `hosts/Default` to a new directory (e.g., `hosts/Laptop`)
+2. Edit the new host's `variables.nix` and `host-packages.nix`
+3. Add the host to `flake.nix`:
+
+   ```nix
+   nixosConfigurations = {
+     Default = mkHost "Default";
+     Laptop = mkHost "Laptop";
+   };
    ```
-  
+
+<!-- 4. Rebuild with the new hostname (see below) -->
+
+4. Rebuild with the new hostname using either `nixos-rebuild` or `nh` (see [Rebuilding](#rebuilding) below). Once rebuilt, any rebuilding method can be used, as the host name will be implicitly recognised.
+
+### Rebuilding
+
+Apply configuration changes:
+
+- **Keyboard shortcut:** `Super + U`
+- **rebuild script:** `rebuild`
+- **nixos-rebuild:** `sudo nixos-rebuild switch --flake ~/NixOS#<HOST>`
+- **nh:** `nh os switch --hostname <HOST>`
+
+Replace `<HOST>` with the name of your host (e.g., `Laptop`).
+
+### Rollbacks
+
+List generations:
+
+```bash
+list-gens
+```
+
+Rollback to generation N:
+
+```bash
+rollback N
+```
+
+Replace `N` with the generation number (e.g., `69`).
+
+### Keybindings
+
+View all keybindings with `Super + ?` or `Super + Ctrl + K`.
+
+## Development Shells
+
+Pre-configured dev shells for various languages are included.
+
+Initialize a project from a template:
+
+```bash
+nix flake init -t ~/NixOS#<TEMPLATE_NAME>
+```
+
+Create a new project directory:
+
+```bash
+nix flake new -t ~/NixOS#<TEMPLATE_NAME> <PROJECT_NAME>
+```
+
+Templates are defined in `dev-shells/default.nix` (python, node, etc.).
+
+Enter the shell:
+
+```bash
+cd <PROJECT_NAME>
+nix develop
+```
+
+If you're using direnv, the shell activates automatically.
+
+<!-- ## Hosts
+
+|     | Hostname   | Board             | CPU                | RAM  | GPU                       | Purpose                                                                            |
+| --- | ---------- | ----------------- | ------------------ | ---- | ------------------------- | ---------------------------------------------------------------------------------- |
+| 🖥️  | `nix-wsl`   | MSI MAG B760 Tomahawk    | Intel I7-13700F    | 32GB | RTX 4070 | Triple-monitor desktop running Windows Subsystem for Linux.                        | -->