Re: Dc/ac
AC power is the same as household current (110v). That's why you can run the same stuff on your boat that you can as if you were in your house. You're getting the AC power via the shore power cords. Once you disconnect, you're operating on 12v battery power and will only be able to operate 12v items, such as haolgen lights, led lights, radio, etc. You may have some items such as a refrigerator that can operate on 110v/12v, but it would have to be a dual purpose built unit. Items such as stoves & A/C units will have to have another source of power.
This is where the (as mentioned above) invertor or generator comes in. Once those units have been activated, you should see the AC panel showing power. Is your boat equipped with either (some are not)?