Instructions
Locate a body of water. Use your arrow keys or number pad to walk into the water until your character is completely submerged. Your character automatically swims when you enter the water.
Watch your air gauge while swimming underwater. When your air gauge is empty, your character begins to drown.
Use the arrow keys to change swimming direction and the 9 and 3 keys on your number pad to pan your view up or down, respectively. Pan your view all the way up and move forward to swim with your head above the surface of the water. Swimming with your head above the surface does not deplete your air gauge.
Swim to the edge of the body of water and walk forward onto the land to stop swimming.