docs: add BUILD.md

Author: flpflan

README.md

@@ -29,33 +29,9 @@ Pre-built versions can be downloaded from the [Release](https://github.com/flpfl
 
 If you want the latest development version, you can also download it from the [CI](https://github.com/flpflan/u-freecam/actions) build artifacts.
 
-## Build (Windows)
+## Build
 
-### Requirement
-
-- Visual Studio (With C++ toolchain and CMake)
-
-### Compile
-
-Open this project directly in Visual Studio, select the `freecam-x86_64-windows` target, and then generate it.
-
-## Build (Android)
-
-### Requirement
-
-- Android NDK 27+
-- Cmake 3.22+
-- Ninja (Optional)
-
-### Compile
-
-```shell
-export ANDROID_NDK=/path/to/ndk # Set the path to Android NDK
-export GENERATOR=Ninja
-make release-aarch64 # Or the other target, e.g. release-x86_64
-```
-
-output: `build/release-android-aarch64/libfreecam-aarch64-android.so`
+[docs/BUILD.md](/docs/BUILD.md)
 
 ## How to Use
 

README.zh-CN.md

@@ -28,33 +28,9 @@ u-freecam
 可在 [Release](https://github.com/flpflan/u-freecam/releases) 页面下载预构建版本。
 如果你想获取最新的开发版本，也可从 [CI](https://github.com/flpflan/u-freecam/actions) 构建产物中下载。
 
-## 构建 (Windows)
+## 构建
 
-### 前置需求
-
-- Visual Studio (包含 C++ 工具链和 CMake)
-
-### 编译
-
-用 Visual Studio 打开本项目，选择 `freecam-x86_64-windows` 目标，然后生成。
-
-## 构建 (Android)
-
-### 前置需求
-
-- Android NDK 27+
-- Cmake 3.22+
-- Ninja (可选)
-
-### 编译
-
-```shell
-export ANDROID_NDK=/path/to/ndk # 设置 NDK 路径
-export GENERATOR=Ninja
-make release-aarch64 # 或者其它目标，如 release-x86_64
-```
-
-输出: `build/release-android-aarch64/libfreecam-aarch64-android.so`
+[docs/BUILD.md](/docs/BUILD.md)
 
 ## 如何使用
 

docs/BUILD.md

@@ -0,0 +1,32 @@
+# Build
+
+## Windows
+
+### Requirements
+
+- Visual Studio (with C++ workload and CMake support)
+
+### Build
+
+Open the project in Visual Studio and build the `freecam-x86_64-windows` target.
+
+## Android
+
+### Requirements
+
+- Android NDK 27+
+- Cmake 3.22+
+- Ninja (Optional)
+
+### Build
+
+```shell
+export ANDROID_NDK=/path/to/ndk
+export GENERATOR=Ninja
+
+make release-aarch64
+# or: release-x86_64, debug-aarch64, debug-x86_64
+```
+
+output: `build/release-android-aarch64/libfreecam-aarch64-android.so`
+