The first step is to identify your wiring at home to understand if you have a Single Pole or 3-Way switch and how you plan to install the dimmer. You must also check to see if you have a neutral wire. If you do not have a neutral wire the dimmer will not work.
You will then need to follow the detailed instructions outlined in the included Installation Guide to label your wires, wire the dimmer and complete the installation.
If you are not sure about any of the steps please consult a qualified electrician for assistance.