To change a light bulb, you will need a new light bulb with the same wattage as the old one, and a ladder if the light is out of reach.
First, turn off the power to the light by switching off the appropriate circuit breaker or fuse in your home's electrical panel. Then, use the ladder to reach the light fixture and carefully remove the old light bulb by twisting it counterclockwise. Once the old light bulb is out, screw the new light bulb into the socket by turning it clockwise. Finally, turn the power back on and test the new light bulb to make sure it works.