You'll need to remove the refrigerator from the RV to attempt the burping procedure. Before removing the fridge, make sure the 110 power is disconnected and the propane gas has been turned off at the tank. Then disconnect the propane gas feed and the electrical feeds (both 110-volt and 12-volt if your fridge uses both).
RV refrigerators are typically shoehorned into place. Study the situation carefully to determine how the fridge is secured to the RV frame and the surrounding cabinets. Take digital photos before beginning each step so you'll have a record of how things fit back together.
There are two general approaches to burping the fridge. The first approach is a little more involved, but takes less time.
Place the unit on one side, and wait until the gurgling stops (allow about three to five minutes). Repeat for the other side, the top, and back to the base. Rock the unit backwards about 45 degrees, hold for three minutes or so, then rock forward to about 45 degrees, and again hold for about three minutes. Plug the unit in or fire it up with propane, wait about four hours, and check to see if it's cooling.
The second approach to burping the refrigerator is to simply stand the unit on its head for about 24 hours, and then set it on its base and carefully level it. Wait until any gurgling stops (the ammonia mixture moving around in the condenser tubes), and fire it up with either 110-volt electrical power or a portable propane bottle. After about four hours, check the temperatures in the freezer and in the food storage section.
