If you can share more details (or a link to where you found the patch), I can write you an exact step-by-step guide.
It looks like you're referring to a specific game mod or patch—likely for Age of Empires II: The Conquerors (often modded as "Conquerors 2.1" or similar). However, I don’t have verified documentation for a mod officially named . conquerors 2.1 fix