Turn off power at the circuit breaker
Verify the power is off with a voltage tester
Remove the existing switch cover plate
Unscrew and pull the old switch out of the box
Take a photo of the existing wiring
Identify the line wire, load wire, ground wire, and neutral if required
Disconnect the old switch wires
Connect the dimmer’s ground wire to the ground wire or ground screw
Connect the dimmer’s line wire to the incoming hot wire
Connect the dimmer’s load wire to the wire going to the light
Connect the neutral wire if the dimmer requires one
Secure all wire connections with wire nuts
Carefully fold the wires back into the electrical box
Mount the dimmer switch to the box
Install the cover plate
Turn the breaker back on
Test the dimmer and light function
Replace the dimmer if it does not work correctly