Place your non-shooting hand into the arm portion of the Jumpshot Trainer as shown in the picture. Tighten strap as needed.
Take the longer portion of the Jumpshot Trainer and wrap it around your forearm placing the small loop around your thumb.
Tighten the Jumpshot Trainer as needed. This will prevent your non-shooting hand from extending and interfering when shooting the ball.
Re-adjust and tighten accordingly to correct your shooting form.