You can don the weight belt at the surface or underwater using a procedure called a weight belt roll. To perform a weight belt roll:

1. Deflate your BCD if you are underwater. Inflate it if you are at the surface.
2. If you are at the surface, place the 2nd stage in your mouth.
3. Hold the end without the buckle in your right hand, and lie on your back. Keep your body straight and horizontal.
4. Place the belt against your right hip. Make sure the belt is positioned with the inside of the belt is against your body.
5. While remaining horizontal, roll to your left until you face the bottom. Your body will roll into the belt, and both ends will hang below you.
6. Continue lying on your stomach while you fasten the belt. Adjust if necessary.