You can go two ways from here. Forward into the trees or right into the open. Go right into the open. There is a kraut down the path and a few at the left in the forest. Kill these and go straight forward. When you walk down you will hear an aircraft engine, run to either side of the road and duck. A plane will strafe the middle of the road (and miss you). You should see a bombed out house. There is a hole in the tall hedgerow at the right. There are 4 krauts there and a truck with a case of grenades and a medkit. After you clear out that area get back on the road and continue where it curves to the left. You will exit into a large open area and see americans in trenches and foxholes.
You've found them, now you must help them defend the position until reinforcements arrive. I suggest that you get in the big trench or the mortar position, other positions are vulnerable to friendly fire. When you get to the far right in the muddy area a C-47 comes in and drops ammo crates. For support you can get on the radio and call in artillery (works once) and use the mortar (ten shells). Eventually reinforcements arrive when they break down the gate that is on the right in front of you. Move towards that position and you get to a "radio box" you end the level by pressing spacebar in front of the box (while ducking).