To replace a headlight bulb, open the hood and locate the backside of the headlight assembly. Remove the connector from the bulb by pressing the release tab, then twist the bulb counterclockwise and remove it from the assembly. Replace it with a new bulb, ensuring it is properly secured, and reconnect the connector. Make sure to consult the manual for the correct type and wattage of bulb needed, as well as any specific instructions for your vehicle.