If it is like mine, there will be a switch to select winterize. I turn another switch to bypass the water heater. Then I get about 3 gallons of antifreeze, a short hose to connect to the winterize connection, the other end in a jug of antifreeze, and turn on the water pump. It will pump the antifreeze from the jug into the water lines. I open a faucet until I see antifreeze come out, close it, and move to the next faucet, until I have done them all including the toilet. That also puts antifreeze in the traps. Also do the outside shower connection. And I have a washer/dryer so I also winterize the pipes to it by running the washer thru the cold line and then thru the hot line it until I see antifreeze in the washer from each. I also open the low point drain lines until I see antifreeze come out each of those.
And I drain the fresh water tank and the water heater. No antifreeze in those.
