Peel off the protective film that covers the door's handle openings. Open the storm door slightly.
Push the latch piece into the hole in the door's edge. Make sure the latch's flat side points toward the exterior. Place a Phillips drill bit in a drill and secure the latch piece in place with the provided screws.
Place the handle with the turn-tab lock through the hole in the door's interior side and put the handle with the keyhole in the door's exterior side hole. Hold the two pieces firmly together.
Drive a supplied screw though each of the screw holes in the door's interior handle. Close the door and test the handle.