Bait the trap by placing peanut butter or something similar on the metal bait pedal (use a Q-tip or toothpick to avoid leaving your scent). Then pull the kill bar back, and swing the arm bar over the kill bar. After latching the bent end of the arm bar into the notch on the metal pedal, slowly release pressure until the arm bar holds the kill bar securely in place. At the slightest little nibble, the metal bait pedal releases the kill bar, snapping the trap closed for an instant kill.