1. First, download the anti-cheat file by clicking on the "Anti-Cheat Download" button below or copying the URL listed below into your browser.

Anti-Cheat Download  

https://dl.gamebuff.cn/tools/%E5%93%A5%E7%89%B9%E8%88%B0%E9%98%9F%EF%BC%9A%E9%98%BF%E7%8E%9B%E8%BE%BE2.rar   

2. After downloading, extract the file to your desktop or another folder. Then open Steam, locate Battlefleet Gothic: Armada 2, right-click the game and select "Properties".

3. Click on "Local Files", then click "Browse Local Files" to navigate directly to the game's root directory.

4. Copy the extracted file "BattlefleetGothic2.exe" into the game's root directory to replace the existing file.

5. Once copying is complete, click "Play" on the game page in Steam to launch the game. After entering the game, open the GameBuff software and click "Add a BUFF" to make modifications within the game.

Note: If you need to restore the original file later, go to the game properties, click "Local Files", and then click "Verify Integrity of Game Files". Alternatively, you can back up the "BattlefleetGothic2.exe" file beforehand.