Click troops to select them. Then use WASD or Cursor Keys to control the troop.Aim with the mouse, 

Click to shoot.Move the mouse to the edges of the screen to scroll around and take a look at what's ahead.Some units need to stop to be able to shoot (namely the Bazooka guy and the Artillery truck)Spys can evade being seen, and transporters can transport troops across the map. Use the evacuate and deploy buttons to switch your units in and out of battle.