Remove all upper body clothing. This includes your shirt and larger sports bras. It is extremely important for the waist trimmer belt to rest against the skin.
Wrap the waist trimmer belt around your body so the thicker area of the belt (the middle) fits in the small of your back. Stretch one side of the belt around the stomach, then wrap around the other side of the belt. A Velcro lining is going to help adhere the two sides of the belt together.
Place your bra and other clothing back over the waist trimmer belt.
Perform your standard workout. This may be anything from jogging for a few minutes to lifting weights. The waist trimmer belt is going to heat up your stomach area that is covered by the belt, causing it to sweat more than usual.
Remove the waist trimmer belt once you have completed your workout and throw it in the wash. If you do not it can quickly begin to smell funny and can even grow mold.