Partisans 1941 - Heroic defense mode - 20 waves withstand

Partisans 1941 heroic defense comes with the back to battle DLC, Its a survival mode in which you get to defend your base until the last breath against the fascist's troops, Its actually pretty tough challenge, I think many people have hardships beating getting the "Defense of Steel" Achievement, I figured out a way and it's really frustrating to execute. If i found many people interested, I will make a detailed guide to how to get to wave 20 plus. I hope you enjoy.