Whilst this is a photo copy, and some of the pages are a little askew, it was all readable and intact. A real bonus finding an old manual for a classic piece of kit that no other site had.
Text excerpt from page 16 (click to view)
Positioning of shelves
Put a screwdriver into the slot of the shelf lock. Turn the screwdriver counterclockwise. Remove the shelf locks from the wire shelf.
Insert the ends of the wire shelf on the left-hand side at the desired position.
Slide the wire shelf to the left. The right-hand side of the shelf will come loose.
Slide the shelf into the holes on the right-hand side.
Lower the right-hand side of the wire shelf and let the left-hand side slide out of the holes in the wall. 16
Slide the plastic plugs into the holes of the wall. Snap the shelf locks onto the wire shelf.