Instructions
Move the right analog stick to move your on-screen cursor. The cursor indicates the general area where your bullets will land when fired. The analog stick lets you aim exactly where you want.
Hold "L1" to look down the gun's barrel. Though this is not necessary, looking down the sight significantly increases your accuracy.
Press "R3" to zoom in on your target. This feature is only available on certain scoped guns, such as the sniper rifle. These scoped guns won't let you aim down the sight. You must aim through the scope.
Press "R1" to fire bullets. Some rifles allow you to hold down the button to fire a stream of bullets.
Press "Triangle" to switch weapons. You can only hold two weapons at any time.
Press "R2" to throw grenades at your enemy.