Turn off power at the breaker
Verify the circuit is de-energized with a voltage tester
Remove the old transformer if present
Mount the new transformer to the electrical box or approved location
Connect the transformer primary wires to the house supply wires
Connect the ground wire to the grounding conductor or grounding screw
Tighten all wire connections with approved wire connectors
Connect the transformer secondary wires to the doorbell circuit wires
Route the low-voltage wires to the doorbell button and chime
Connect one transformer secondary wire to the chime transformer terminal
Connect the other transformer secondary wire to the doorbell button circuit
Connect the doorbell button wire back to the chime front terminal
Connect the chime common terminal to the remaining transformer or button wire as required by the chime diagram
Secure all wires and close the electrical box
Restore power at the breaker
Test the doorbell button and chime operation
Shut off power again if any wiring needs correction