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docs/en/develop/index.md

@@ -1,4 +1,49 @@
-# Start Developing
+# Developer Guide
 
-<!-- TODO: Developer introduction, environment setup, required PHP extensions.
-  Link to Vendor Mode for library authors, and Contributing for code contributors. -->
+This section covers the StaticPHP development workflow and the foundational knowledge needed to understand how StaticPHP works under the hood.
+
+## Overview
+
+StaticPHP is a binary build tool whose core purpose is managing the build pipeline — downloading and configuring PHP source code, resolving extension dependencies, and invoking the underlying build system (e.g., Docker or a local compiler).
+
+From a development perspective, StaticPHP is an open framework that provides the ability to statically build PHP and other open-source tools together. The project is maintained by [@crazywhalecc](https://github.com/crazywhalecc) and [@henderkes](https://github.com/henderkes), with contributions from the community.
+
+You can think of StaticPHP as a typical PHP CLI project built on [symfony/console](https://symfony.com/doc/current/components/console.html).
+
+## Development Environment
+
+To get started with StaticPHP development, you'll need a PHP development environment with the required dependencies installed.
+
+Requirements:
+
+- PHP 8.4 or later
+- Composer
+- Git
+- PHP extensions: `curl, dom, filter, mbstring, openssl, pcntl, phar, posix, sodium, tokenizer, xml, xmlwriter`
+
+> These PHP extensions are required for StaticPHP's `dev` environment.
+
+### Setup Steps
+
+1. Clone the repository:
+
+    ```bash
+    git clone https://github.com/crazywhalecc/static-php-cli.git
+    cd static-php-cli
+    ```
+
+2. Install PHP dependencies:
+
+    ```bash
+    composer install
+    ```
+
+3. Verify the setup:
+
+    ```bash
+    bin/spc --version
+    ```
+
+---
+
+You can continue reading [Project Structure](./structure) to learn more about StaticPHP's framework architecture.