IKEA Besta Manual page 9

Step 8
A. Rotate the shelf 180
degrees so that the
slider bar faces you.
B. Place the clips (#124187) on the
slider bar by putting the top lip in the
top compartment, then rotating the
clip downwards into the bottom
compartment until it clicks in. Refer
to the picture on the left.
C. Place one clip above each vertical support
piece, along with one directly in the middle
of each outer segment, and two pieces in
the middle of the center segment, splitting
the center segment into thirds.
Step 9
A. Slide the clip that was just placed a
few inches away from the end.
B. Screw down the L shaped piece
(#124185 and 124186).
C. Line up the holes on the shelf and L
shaped piece and have the vertical
part of the L shaped piece line up with
the outside of the shelf.
D. Use the pointed screws (#109049).
Slide the clip back until it touches the
piece that was just placed.
E. Repeat this step on the other end.