Installing a Light DimmerIf there's one thing that can make a room look glamorous in two seconds, it's lowering the lighting. When you're choosing a dimmer, you need to know if it's a single pole or a double pole, as well as the wattage it will control. That depends on how many light bulbs the dimmer will handle.
Since you're dealing with electricity, you need to be careful. Spend $4.00 on a tester so that, once you flip the breaker switch off, you can make sure there is no electricity in the circuit. Any time you're working on electrical, you must make sure the power's off. Follow the instructions for the tester to ensure that there is no juice flowing.
Once you've determined that there is no power to the switch, unscrew those two screws. You'll be left with two wires. The dimmer also has wires. Twist the two black wires of the dimmer onto the two wires coming out of the wall. If you have a metal box, you don't need to worry about the ground wire; just screwing the black wires onto it will ground it. If the box is plastic, though, you must connect the green wire.