The answer to 'how to replace lighting installation' is to carefully follow the steps to safely remove and replace the existing lighting fixture. First, turn off the power to the lighting circuit at the circuit breaker. Use a voltage tester to confirm the power is off. Next, remove the old fixture by unscrewing the mounting screws or nuts that hold it in place. Disconnect the wires, taking note of where each wire is connected. Install the new fixture by connecting the wires according to the manufacturer's instructions, usually matching colors (black to black, white to white, and green or bare copper to the green or bare copper ground wire). Secure the new fixture in place and turn the power back on to test the new installation.
It's important to take safety precautions when working with electrical wiring. If you are not comfortable with the process or do not have the necessary tools and skills, it's best to hire a licensed electrician to handle the lighting replacement.