In the first tank mission in Africa, there is a Flak 88 gun that will destroy one of your tanks. The gun is on the right side inside a building and is not visible. Shoot the second building on the right side. It is the tallest one and will start to crumble when hit. Also, some of your troops are on the right side. Do no run them over. They will help you by taking out the other Flak 88 gun. All you have to do is take out the two machine gunners on the right side after the first Flak 88 gun.