Linda, my wife is on her third trailer but has kept me.
If you understand emptying the H2O heater and changing the valves to bypass it, the rest is pretty easy.
Buy 3 gallons of the red RV antifreeze.
Open your low point drains and all of your faucets and let the water drain out. At the same time, open the tank drain for your on board water. After all of that stops draining, close the valves and faucets.
There should be an intake hose near the water pump to siphon the RV antifreeze into the system. You'll need to turn the valve to open it. insert the hose into a gallon of antifreeze. turn on your water pump, then go from faucet to faucet turning them on until you see the antifreeze flowing. You need to watch the antifreeze level in the jug as once it gets low you'll change it to a full one. Make sure you do EVERY faucet, including outdoor kitchen and shower. Once you have done that, shut off the water pump.
I always pour a bit of antifreeze into my emptied holding tanks as added insurance.
As far as where your water tank is, look under your rig for a drain. you should have two low point drains and another for the water tank.
The hose to pump the antifreeze in is normally close to the water pump.
Hope this helps.