Turn off the power. Make sure the power is off first. The fuse box's big red power button should be turned to "off" for the safest method of doing this.
Let it cool. Before touching the bulb, give it time to cool.
Use a ladder. Use a stepladder to make sure you can reach the bulb safely.
Remove bulb. Remove the lightbulb from the socket.
Replace the bulb. Lightly but firmly press a new bulb into the socket. Depending on the kind, slowly twist it clockwise until it locks into place or until it won't spin any further.
Restore power. Restart the power once the bulb has been installed, then turn on the light.
Dispose of the old bulb. The old bulb's broken, highly sharp glass needs to be disposed of securely. To safely dispose of the old bulb, wrap it in the packing from the new one.