Actually, it was a tripple, and I didn't know if you were looking in here so I was going to delete the last two.
Anyways, this is not a real time strategy game. You can take as much time as you like deciding which units to move. Once you decide to move them the defense becomes active and will shoot at you if you are within range. If they can't see you they won't shoot at you. Once you initiate your attack, they will do a standard counter attack.








