Measure the size of the opening across the brick mold for the width and from the brick mold down to the floor for the height. Brick mold is the trim that is around the exterior door and will be where the security door is installed. Record the measurements of both the height and width so the proper door can be installed.
Open the security door and locate the Z-bar. The Z-bar is a piece of metal that is located on the hinge side of the door. Cut the Z-bar with a hacksaw so it is 3/16 of an inch less than the height of the door being installed.
Set the door in the opening from the outside and place a level on either side running vertically to make sure the door is square and plumb. Line up the hinges to the brick mold and pre-drill a hole through each hole in the hinge. Attach the Z-bar and hinges to the door with 2-inch screws.
Install the header along the top of the door. Slide it over top of the door and install it into the pre-drilled holes with pan head screws. Cut the top of the Z-bar with a hacksaw so it is 1/8 of an inch taller than the door.
Slide the door sweep under the bottom of the door and pre-drill 1/8-inch holes through the slots in the sweep. Secure the sweep to the door with 1-inch screws. Line the closer up in the top center of the door and screw it in place with the provided screws. Attach it to the jamb with 2-inch screws and test the door out to make sure it is working.
Install the hardware in the pre-cut opening for the holes. Screw it in place and make sure the door opens and closes properly upon completion.