There are a couple of forum members with Four Winds 31L's, and it is probably essentially the same coach, so they might be able to help (if they winterize their coaches).
Otherwise it is not a huge deal, mostly winterization is related to the water system.
Depending on what CW did (blow lines, use antifreeze, etc) the procedure might differ a bit.
Basically the procedure is to un-bypass the water heater, put the heater drain stop in, make sure the low point drains are closed, fill the tank and/or connect city water, then run the hot side first.
Open the overflow vent in the water heater until water comes out. That way you'll know it's full.
Then turn on each faucet one at a time - first the hot side, then the cold side - until you bleed all of the air and pink antifreeze out of it.
If you have pink antifreeze, you might want to run the water a little longer.
Then fill the water tank and fire up the pump and run it awhile too.
At some point you will have to drain your holding tanks.
Of course, the other stuff is needed too; oil change for the genny and engine (but you should have done that in the fall), top off battery fluids, air pressure in the tires, and so on.
The only thing that works on a RV is the owner...