GE GTH21 Owner's Manual And Installation Instructions page 6

About the shelves and bins.
Not all features are on all models.
Lift up
and out
Tilt up
6
Rearranging the Shelves
Shelves in the refrigerator and freezer compartments are adjustable.
Refrigerator Compartment
Half-Width Shelves
One end of the shelf rests on a
molded side-wall support; a bracket
on the other end hooks into a track
on the rear cabinet wall.
To remove:
Tilt the shelf up at the front.
Lift the support off and out of the track.
To replace:
While tilting the shelf up, insert the top
hook at the back of the shelf in a slot
on the track.
Lower the front of the shelf until the
bottom of the shelf locks into place.
NOTE: The shelf to the right of the track is
designed to hook into the right-hand slot; the
shelf to the left is designed to hook into the
left-hand slot.
Freezer Compartment
To remove:
Lift up the left side of the shelf and
slide it left into the center of the shelf
supports.
Rotate the right side of the shelf up and
out of the shelf supports.
To replace:
Holding the shelf diagonally, insert the
left end of the shelf into the center of
the shelf supports on the side wall.
Insert the right end of the shelf into
the shelf supports on the side wall.
Rest each end of the shelf on the
bottom of the shelf supports.