1. The number of additional switches or outlets should be counted that are required to gang together in the electrical box.

2. The side-plate retaining screw on the bottom left-hand side of the electrical box should be removed. By turning the screw counterclockwise using the appropriate tip screwdriver it should be removed it from the mounting bracket.

3. The side plate of the box should be removed by pulling the plate tongue out from the slot which is situated at the opposite end of the retaining screw mount.

4. The side plate of the box should be removed which is to be joined to the first box in the same manner as instructed above.

5. The add-on box should be attached by pushing the tongue end of the box into the slot present in the first box.

6. The retaining screw should be installed in the mounting bracket and tightened.