Turn off the main power to the panel
Verify power is off with a voltage tester
Remove the panel cover
Identify the faulty breaker
Note the breaker type and amperage
Disconnect any wire connected to the breaker if needed
Release the breaker from the bus bar
Remove the breaker from the panel
Install the new breaker in the same slot
Reconnect the wire to the new breaker
Ensure the breaker is fully seated and secured
Reinstall the panel cover
Turn the main power back on
Test the new breaker
Call a licensed electrician if you are unsure or uncomfortable