Well the chance you will find photos and instructions with your exact plumbing layout are small. There are two ways to do this. One is to blow out the lines and the other is to fill the system with antifreeze. I use the first method but there are some in colder climates that prefer the antifreeze method. Anyone can blow the lines out. All you need is an adapter that hooks to the hose connection and has a quick disconnect for an air compressor on the other end. You can put one together from parts at Lowes or Home Depot. You need to drain the water heater and then reseal it. You set the regulator to about 60psi and let the pressure build up and then open valves till little or no water comes out. Do this several times and come back to places you have purged before and do them again. Pay special attention to low points like the toilet flush valve. Also don't forget the shower. You may find a low point drain outside under the trailer where the tanks are and you can open that as well. Not a bad idea to pour some antifreeze in the drain traps.
AND don't forget to remove any water filter elements you may have. I had one built into the kitchen sink fixture. Moen no longer supports these and replaced mine with a similar type faucet, no filter and pull out sprayer. We also have a previous owner installed whole house filter. I keep xtras on hand and put in a new one for the spring.
Roger in NJ
" Democracy is the worst form of government. Except for all the rest"
Winston Churchill 1948