How to beat that mission is:

1st: Go to the room on your guys right go down the stairs. Shoot the krauts that is behind
the destroyed fence-like-post.
When that is done, go to the left of your character, head for the trench that leads to the
left Pillbox, carefull, almost all the krauts has MP40s.

2nd: After you clear that PB out, go for the center PB trench, there will be more krauts
there, this will get a bit tougher, I would go to crouch so you dont get hit by the MG42
in the Control Bunker. All you have to do is clear that one out then head to the right PB
Trench.

3rd: When you get into the Right PB Trench, you will find a path that leads into a shelter
room with a light in it, there you will find a Machine Gun. You can collect it if you
want. After you clear the Right PB from the krauts, you will be fighting even more krauts.

4th: When you are on the German Control Bunker (GCB), You will have to go through the back
and continue thorugh the GCB Trench, there will be atleast 20-25 Krauts you will be
killing. After that, You will be fighting atleast 9 Krauts, after you take them out,
BINGO, you take down the flag.