Class C Gulf Stream 4230 Sprinter Motorhome

I'm reading thru all the manuals and paperwork I received when I purchased this motorhome used a couple weeks ago. It's a 2007. Does anyone have one like this? I'm reading about the hot water bypass and an antifreeze tank. Where is this antifreeze tank located on yours ? I'm used to my trailer and just turning the bypass valves and sticking the hose in the gallon of antifreeze and turning on the water pump. The directions aren't clear to me in the operating manual for Prevent-A-Freeze