Here are the steps on how to change a light bulb in a flush mount fixture:

1. Turn Off Power: The first step is to make sure that the power to the light fixture is turned off. This can be done by turning off the light switch that controls the fixture or by turning off the circuit breaker that powers the room where the fixture is located.

2. Access Fixture: Next, you need to access the flush mount fixture. This can be done by either removing the fixture from the ceiling or by removing the cover of the fixture. The method of accessing the fixture will vary depending on the specific type of flush mount fixture you have.

3. Remove Bulb: Once you have access to the bulb, gently twist it counterclockwise to remove it from the socket. Be careful not to apply too much pressure or you may break the bulb.

4. Replace Bulb: Take your new bulb and gently twist it clockwise into the socket. Make sure the bulb is securely in place.

5. Turn Power On: After you have replaced the bulb, turn the power back on to the light fixture. This can be done by turning on the light switch or by flipping the circuit breaker back on.

That's it! You should now have a working light bulb in your flush mount fixture. If you have any further questions or concerns, please don't hesitate to let me know.