Just plug it into any of the standard plugs inside the MH. As long you have your MH plugged into shore power, all your plugs should be live 110v AC. None of your standard household type plugs will have 12V to them. The only 12V outlets will be the round, cigarette lighter/accessory type of plugs.
Depending on what is sharing the circuit that you have your MH plugged into, you should pay attention to what all you have on in the MH at any given time so that you won't trip the breaker on that particular circuit. This is important when running the vacuum cleaner, microwave, TV etc. in the MH while plugged in at home. Chances are, you're plugged into a 15 amp or possibly 20 amp circuit at best, so you'll only be able to draw only so much power at one time.
