Turn off power at the circuit breaker
Verify the power is off with a voltage tester
Remove the switch cover plate
Remove the switch from the electrical box
Identify the incoming hot wire, the wire to the light, and the ground wire
Connect the incoming hot wire to one switch terminal
Connect the wire to the light to the other switch terminal
Connect the ground wire to the green ground screw
Secure all wire connections with wire nuts if needed
Mount the switch back into the electrical box
Install the cover plate
Turn the power back on at the breaker
Test the switch to confirm the light works