Turn off the circuit breaker for the switch
Verify the power is off with a voltage tester
Remove the switch plate cover
Unscrew the switch from the electrical box
Pull the switch out gently
Take a photo of the wire connections
Loosen the terminal screws or release the wires
Remove the old switch
Connect the wires to the new switch in the same positions
Tighten the terminal screws securely
Fold the wires back into the box
Screw the new switch into the electrical box
Reattach the switch plate cover
Turn the circuit breaker back on
Test the new switch