For unlocking of a trunk lid from outer side, insert the main key and turn it clockwise.
For closing of a trunk lid lower it and press it down. After closing of a cover of a luggage carrier / a back door try to pull it up and be convinced that it is reliably locked.
Prevention
During driving you hold a luggage carrier cover / a back door closed.
Fixing removal lever
For unlocking of a trunk lid from the driver's seat, pull the fixing removal lever up.