This is easy but you might need a mouse also (for camera angles, I haven't done it in years so I can't remember if I used keyboard only) you use W, A, S, D to move I think W and S is:
S - down
D - right
Here's a nice little trick:
E- rotate right
Q-- rotate left
The rotation helps out allot!!!!
Now as for the mouse if I am correct you used the mouse to keep the camera behind the little chopper so that you are able to see where you are going at all times and not hit anything and explode