If you can find the brand name on the winterization valving, tank, or switch, it would help greatly. Swan Industries
is one brand of automatic winterization kits for both home and RV installations.
The complete winterization kit
is $599 through their Amazon store. I did not find their instruction/owners manual online though.
I have my owners manual in the MH, but I forget the brand Winnebago used in their Ultimates.
The hydro-hot system should already have anti-freeze in it, but the concentration should be checked if you are unsure.
For MY MH only, I drain the fresh water tank and lines, remove the whole house/MH water filter,drain outside shower, etc. flip the water heater bypass switch, fill the RV anti-freeze tank, then flip the winterization switch. This turns on the water pump, which draws from the RV anti-freeze tank, which fills the lines-pushing out any remaining water. The clothes washer is a separate procedure for winterizing, but is still supplied by the winterization unit.
I hope that was clear enough to make sense.