The motion-detector and the door/window-contact which are included with the alarm system , are already paired. The door/window-contact is linked to Zone 1 and the motion-detector is linked to Zone 2.
This means that the next sensors being paired will be linked to Zone 3, Zone 4 etc. Make an notice of this one, so you will know which sensor is linked to which Zone. Amongst others handy when applying an name to an Zone (till max Zone 9).
Do you want to start from point zero and self-decide which sensors are going to be linked to Zone 1 and 2, then press 3 times on the "antisabotage button". All sensors will be unpaired, including all accessories.