Start the vehicle engine with the E key.
Shift gears with Q and W keys.
Push joystick forward to accelerate. (Once you are at speed you can release stick.)
Pull joystick back to brake.
Steer left/right with joystick.
To select ammo types in tank, you need to map a key. Pull up the clipboard (ESC key), the go to Setup/Keymap/Gunner and map a key to "Select primary". (I use the Backspace key.) That key will then toggle between ammo types.
Enjoy.

popeye