For a simple vehicle, you need:

4 tire.sur
3 body1.sur
2 cyl.sur
1 gun1.sur
1 turret1.sur

Line body1s next to each other (abreast).  The indents on the outside are
wheel-wells; put the tires here.  The cyls fit across the top in the "top
wheel-wells".  The turret1 stands straight up on top, and the gun attaches
to it.

Good Luck.

