Opel Automobile Owner's Manual page 64

64 Storage
Installation of hooks in the rails
Insert the hook in the desired position
firstly in the upper groove of the rail
and then press in the lower groove.
To remove firstly pull out of the upper
groove.
Service box
Install two hooks in the upper rail.
Insert upper brackets of the box from
above into the hooks.
Alternatively install both hooks in the
lower rail. Plug in the lower brackets
of the box from above into the lower
hooks.