How to install thermal expansion tank on water heater /replace expansion tank, Prevent an explosion

If your temperature and pressure valve on your water heater malfunctions, you are on a closed system (see video), and you don't have an expansion tank, the hot water expanding may have nowhere to go and could damage your heater or cause an explosion. So how to install expansion tank on water heater? Replacing an expansion tank is even easier. House pressure gauge used in the video: https://amzn.to/4eDOXGs, tire pressure gauge for filling and testing air on expansion tank: https://amzn.to/4erPiwf, affiliate links.