Choose a door to install the sensor on.
Locate an area along the same wall on which the door is located to attach the main component of the security sensor, i.e., the wireless receiver.
Hold the receiver against the wall in the space that you have selected. Draw marks with a pencil to indicate where the unit will be installed.
Make a hole in the penciled-off area to create an anchor for the security unit. Use a power drill to pierce into the wall. Insert a screw with a screwdriver into the drilled hole. Screw it in almost all of the way into the wall.
Hang the receiver unit on the wall. The bracket is the small indentation on the back of the unit that fits over the screw in the wall.
Attach the metal sensors to the door and the door frame. Mark off where the magnetic sensors will be placed on both the door frame and the door. The sensors must come into contact with each other when the door is closed to create a connection.
Drill holes for the magnetic sensors and secure the sensors in place.