Turn off power at the breaker
Verify the circuit is de-energized with a voltage tester
Remove the switch cover plate
Unscrew and pull the existing switch out of the box
Take a photo of the current wiring
Identify the hot wire, load wire, neutral, and ground
Disconnect the wires from the old switch
Connect the hot wire to the switch line terminal
Connect the load wire to the switch load terminal
Connect the ground wire to the green ground screw
Connect neutral only if the switch requires it
Tighten all terminal screws securely
Fold the wires neatly back into the box
Mount the switch to the electrical box
Install the cover plate
Turn the breaker back on
Test the switch operation