Attach sensors to every door and window in the house. If you don't have enough sensors with your system, you can usually order additional ones. The sensors attach to your doors and windows with an adhesive and they come in two parts. The transmitter sticks to the door or window frame. A magnet attaches across from the sensor on the door or window itself. If the door or window is opened while the system is active, the magnet is separated from the transmitter, which sends a signal to activate the alarm.
Determine the location for your control panel. It should not be visible from any windows looking into the house, but it needs to be close enough to the main door so you can turn it off quickly when you get home. You also need an electrical outlet nearby on the same wall.
Drill a single hole into the wall where your panel will go. Your system's main power will still be wired to an electrical outlet.
Drill a second hole under the outlet you're using for the panel.
Run the power cable for the panel from the first hole, through the wall and to the second hole so you can plug it into the outlet. The control panel will go over the first hole so it is not visible.
Repeat the install procedure for the siren by drilling one hole in the wall where it will be located and a second under the outlet it will plug into. The siren's power cable will run through the wall to the outlet.
Plug the alarm code into the siren. The procedure for this varies from one system to another, but it is very common to use a screwdriver to flip a series of switches on the side of the siren to set a numerical deactivation code.
Program your control panel. There will be an instruction manual telling you how to do this since it varies depending on the individual system. Your disarm code needs to match what you put on the siren.
Run a test of your system to ensure all the sensors and the siren are functioning properly.