Open all of the gas valves to the refrigerator. Depending on the model of refrigerator in your RV, you may need to open the gas cylinder valve and a shut-off valve for gas supply to the fridge.
Reset the main power button by switching it to off, waiting up to a minute, and turning it back on. The fridge will be in the "Auto" mode by default. In this mode, the refrigerator uses the most convenient form of power available, whether it is gas or electric, so the pilot may not automatically light.
Press the mode button to switch the refrigerator to "Gas" mode. Your particular model may have an LED display or a light that comes on next to a flame or other gas symbol to indicate the unit is now in gas mode.
Watch for the pilot light or burner jet to automatically ignite the refrigerator's burners. If the first attempt fails, most RV refrigerators have a control system that will make another attempt after about 30 to 45 seconds. If the refrigerator has not been used in some time or you've just refilled your propane tank for your RV, there may be air in the gas line and it will likely take several attempts before the pilot light will ignite.