Wireless home security systems come in a kit that includes a main module, door sensors, window sensors, motion sensors and a siren. Pre-program the module before affixing it to the wall. Position the mounting bracket for the door sensor on the entry doorframe, and mark the drill holes. Drill pilot holes, and mount the bracket with screws. Remove the cover from the magnet, and screw it into position on the door so that it is directly next to the sensor.
Many sensors have an LED indicator to show whether the magnet is positioned properly.
When the magnet is in position, replace the cover. Install the window sensor to the wall in the same manner as the door sensor. Attach the glass-break detector to the window glass. Remove the sensor body from the mounting bracket, remove the cover, and back out the terminal screws. Attach the wires to the appropriate terminals, tighten the screws, replace the cover, and attach the sensor to the mounting bracket.