Attach the Dimmer Switch
There will be three wires: one black, one white, and a separate ground wire that may be bare copper or is sometimes wrapped in green. Inspect the quality of the wires. If any of the wires seem weakened, trim and re-strip the end of the wire to meet your needs.
Identify the three different colored wires, and attach the new light switch to the wires in the same way they had been attached to the old switch. If your wires are solid copper, create a loop in the end of the wire with the pliers and guide it around the screw on the side of the switch. Tighten the screw, ensuring that the wire is securely held beneath the screw and is not splaying to the perimeter of the screw. If your wall wire is composed of a group of smaller wires, use the pliers to gently twist the ends of the wires together to make them “whole,” and then follow the same direction.