How do I replace a 10 gal Atwood water heater?

thanks for all your replies and an email from another Alfa owner. Yes, there is access at the back....a plastic box cover held in place by screws and caulking. New unit is ordered but wont be here til Wed. altho now I may wish I had not done that. The leak appears to be AT a fitting where one of the hoses enters the tank...something that might be replaceable. Wednesday or so I will find out.