I agree. You have a lot to learn. There are many different configurations for RV's. You must learn how yours is configured. You may get confusing advice because there are many different configurations.
The picture posted above says a lot. Get started hooking up like the picture. Yours will be similar, but maybe not identical. This will be good until you encounter freezing temperatures. You can leave the fresh water holding tank empty. Water will be supplied through the "City Water" connection.
There will be a garden hose like connector marked "City Water". There will possibly be an identical fitting marked "Black Tank Flush". Do not connect the shore water line to the "flush" fitting. If you do, the black tank will fill and overflow some where.
Good advice above on closing dump valves. Learn how to flush the black tank soon. Search for "How to dump RV tanks". There are many different methods. Don't let that confuse you. Ask specific questions here on iRV2 if you need help.
You will need a separate hose to flush the black tank and dump hoses. It should not be white in color so you can easily tell the two hoses apart. Keep the white potable water hose separate and away from all dump hoses and fittings.
Open the gas valves on the propane tanks. Operate the valves slowly. Opening them fast may cause the safety valve inside to shut down the flow for a while. Check for gas working properly by lighting the cook top burners for a minute.
Most switches should be turned "on" at least to start with.
Don't turn the electric water heater on unless you are certain it is full of water. It will only take a moment to melt the heating element if not covered in water.
Water pump switch should be "off" when on-board water tank is empty. It will wear out fast if run dry.
You have two electric power systems. One is the "shore power". It may be 30 amp 120 volts, or it may be 50 amps 240 volts. The other system is the 12 volt system.
Shore power provides power for:
If you have a 30 amp 120 volt system, a circuit breaker may trip if you try to operate too many of these devices at the same time. Just turn something "off" and reset the breaker.
12 volt system runs using shore power running the the on-board converter/charger or from the on-board batteries:
Water heater and furnace controls
Air Conditioner controls (possibly)
Water pump when not using "City Water"
Propane leak detector
There may be a battery disconnect switch near the battery and/or a switch near the entry door. The one near the door will turn power "off" to most, but not all 12 volt devices. Leave it "on" when unit is occupied.
Use the switch near the battery to totally disconnect for storage.
I presume you want to preserve the battery bank even though you don't want to use it.
Store lead acid batteries fully charged. This means 14 to 18 hours charging using the on-board converter/charger. Re-charge before voltage on the battery terminals drops to 12.4 volts. Get a digital volt meter from your local hardware store. It may cost $15.
You can store lead acid batteries disconnected for 6 months when they are in good condition. Check battery voltage periodically and do a full recharge before voltage drops below 12.4 volts.
Check voltage frequently to start with. Decrease frequency of checking later. You will get to know how long it takes to self discharge.
Check water level in flooded cell batteries and fill to full mark AFTER
charging. They may overflow if you fill before charging.
Plates must be covered while charging. Look through fill holes. You should see water (acid) inside. Add enough to cover the plates and then charge.
Alternatively, you can store lead acid batteries connected to the on-board converter/charger. Monitor water level if you have flooded cell batteries. Check frequently to start with. Decrease frequency after you get to know how often the batteries need filling.
Some battery designs are sealed. This type does not need water level to be filled or monitored. They still need monitoring for voltage when disconnected.
Google search is your friend. Search for instruction on how to manage your new home. iRV.com is an excellent source for answers to specific questions.
Make and model of your RV, and make and model of each appliance are required for best answers to questions about them. Spend a little time collecting them for future questions. You may get a set of appliance manuals for your systems. Keep them handy. They are probably available on-line as well. I have down loaded them for all my appliances.
Most RV parks and camp grounds have friendly neighbors. Make friends and ask for advice. Some of us love to show off our knowledge.
I wish you good luck and happy trails ahead!