5 Install the coupling brackets.
Position the two racks side by side.
Adjust the leveling feet on both racks so that the racks are parallel and
in the same horizontal plane. For instructions, see "Adjusting the
Leveling Feet" on page 23.
To install the coupling brackets on the racks, hook the brackets into
the square holes inside and adjacent to the rack posts, and tighten the
brackets using the wing nuts (see Figure 1-19).
Figure 1-20. Coupling Two Racks
coupling bracket locations
coupling bracket (4)