Turn off the main power supply
Verify the circuit is de-energized with a voltage tester
Remove the panel cover screws
Take a photo of the existing breaker wiring
Disconnect the wire from the old breaker
Release the old breaker from the panel bus bar
Remove the old breaker
Match the replacement breaker to the panel model and amperage rating
Install the new breaker onto the bus bar
Reconnect the wire to the new breaker
Tighten all connections securely
Reinstall the panel cover
Turn the main power back on
Test the new breaker for proper operation