Turn off power at the breaker
Verify the power is off with a voltage tester
Remove the switch cover plate
Remove the existing switch from the electrical box
Identify the hot wire, load wire, and ground wire
Connect the hot wire to the switch common terminal
Connect the load wire to the other switch terminal
Connect the ground wire to the green ground screw
Tighten all terminal screws securely
Fold the wires neatly into the box
Mount the switch into the electrical box
Reinstall the cover plate
Turn the power back on at the breaker
Test the switch