Press Win + R then copy and paste : %localappdata%
Find the folder named after the game you want to patch
Then go to Saved\Config\Windows (or Saved\Config\WinGDK if you're using a Microsoft Store version of the game)
Copy and paste the engine.ini file you downloaded here, if there already is a engine.ini present in the folder rename it and keep it just in case something goes wrong
In case the game tries to modify the file you just installed here, right click the engine.ini file then go to properties and turn the read only on and apply
You should be good to go now, but in case you have issues or worse performance, revert to the original file.