If you are plugged into shore power and have city water connected -- open a hot water faucet and be sure cold water runs out of it. You do this to ensure that the 6 gallon tank on the water heater is full of water. If it's not you can burn out the electric heater element in the hot water heater. Go to the Monitor Panel on the side of the upper kitchen cabinet and turn the last switch on the bottom right ON. This provides power to the electrical element in the water heater. Wait about 10 or 15 minutes and you should have hot water.
If not using shore power. Be sure the fresh water tank is full. On the Monitor Panel turn on the Water Pump. The red light above the switch should turn on. Open any hot water faucet to be sure the water heater tank is full. The water pump will cycle as the water runs. Be sure that the valve on the propane tank is open. You might want to light a stove element for about 15 seconds or so to be sure that the propane has forced the air out of the propane line. Turn off the stove element and go to the Monitor Panel and turn on the switch that says LP Gas for the Water Heater. Again wait about 10 or 15 minutes and you should have hot water.
To help yourself understand how everything works on your RV, I wrote an Owners Manual. It is available to be downloaded at this link on the forum:
. Just go down to the link contained in the description and follow the instructions for down loading the manual.