1. First download the anti-cheat file by clicking "Anti-Cheat Download" below to download.  

Anti-Cheat Download: https://dl.gamebuff.cn/tools/%E5%96%8B%E8%A1%80%E5%A4%8D%E4%BB%87.rar  

2. After downloading, extract the files to the desktop or another folder. Open Steam, locate "Back 4 Blood", right-click the game, go to "Properties" → "Browse Local Files" to find the game's root directory.  

3. Copy the extracted file `start_protected_game.exe` to the game's root directory and replace the existing file.  

4. After completion, click "Start Game" on Steam to launch the game. Once in-game, open GameBuff and click "Add a BUFF" to modify settings.  

**Note**: To restore files, go to game properties, click "Local Files" → "Verify Integrity of Game Files", or restore from a backup of `start_protected_game.exe`.