Decide which country you want to attack. Get your men to the other side of the map without letting the enemies men get to yours. Everytime one of your men gets to the other side, the territory bar will move slightly to the right, and when the enemy gets to your side, the bar will move left. You control the yellow arrow on the left, it indicates where you are to create your soldiers. You can move it up and down by pressing W and S (or Up and Down).