That’s a good way to need a plumber. 90% of people should not attempt changing an aerator let alone an anode rod. Those things don’t just come out most of the time. Even if you do have clearance you should disconnect the water and gas lines just from danger of the water heater twisting when your wrenching them out. Everything on a water heater is technically easy but if you go into it thinking it’s going to be without having done it your setting yourself up for failure.