Your RV should have two sources of power available if like most RVs. You have 120 VAC based on either 50 amp or 30 amp service. The AC is provided either by an on board generator or "shore power". If you look at the mains power in circuit breaker panel the mains breaker should be either 30 or 50 amp depending on the service the system uses. I am assuming your location to be US. The 50 amp service panels usually bring in 240 VAC split phase mains power just like a US residence. The cable used for the "hitching post" will be wired accordingly with the correct connector.
The RV also uses 12 VDC power for all the accessories that run on and require 12 VDC power. The 12 VDC power is provided by battery power and a 12 VDC converter. When running from 120 VAC the converter provides all 12 VDC power as well as charging the batteries.
If the RV has standard 120 VAC power outlets they should be wired identical to residential outlets. There is 120 volts hot or high, a neutral and a ground. Attached are some outlet images with resulting voltages. The first two images show measuring neutral to hot with the resulting voltage. The last image shows hot to ground. The voltages should be the same give or take. This shows that Ground and Neutral are tied together at the mains breaker panel. This can be done using a meter as shown or just go to any hardware or home improvement store and buy a simple 3 lamp outlet tester for about $10 USD.
The 12 volt negative power and the 120 volt neutral and ground should all be the same point. In the case of an RV this should be chassis ground.
Ron