It is very easy to install a dimmer switch as long as the process is completed in the proper order. The first thing that you must do is pull out the fuse or turn off the circuit breaker that corresponds to the dining room. Remove the light switch box by disassembling the black and white wires from the screws on the box. Then connect the two wires from the dimmer switch to the two inside the wall. It does not matter if the wires connected to the dimmer switch do not match in color to the wires in the wall. Make sure that the wires are covered with plastic connectors, attach the dimmer switch to the wall and the job is done.