Answer
Well there is keyless operation which sends a rf (radio frequency) to a central locking control module which in turn activates the door actuators to operate the door locks, or with a key type you insert the key and turn the barrel of the lock and the actuator (attached to lock) is activated and sends a signal to the control module which activates the central locking for all doors, same thing with a push button - it sends a signal to the control module.