Just before the water pump inlet is a valve that redirects water from the fresh water tank to the antifreeze port. Turn this valve so that the water pump draws from the antifreeze port instead of the fresh water tank. (I assume you have the hose from the antifreeze port sticking into a gallon of antifreeze).
There are 3 valves at the back of the hot water tank. These need to be turned, if you haven't already done so, so the antifreeze doesn't run into the hot water tank.
If you have not already done so, the water filter canister needs to be removed and emptied and the filter element removed. Then re-attach the filter canister.
With mine I run the antifreeze through the hot water lines first, starting closest to the water pump and then do the cold water lines, Don't forget the shower, toilet and outside shower lines.
While I'm in the camper running the antifreeze DW is outside and alerts me when each antifreeze gallon is about emptied.
2015 Shamrock 231KSS, Oyster shell
2019 Chev Silverado LT Z71 Ext. Cab, 4x4, 5.3L V/8
Reese Straight Line WDH, 2000W Honda Gen.
2 Old Town kayaks & 2 Boston Terriers - Zoey/Gonzo
Lar & Ruth
55 nights camping 2015, 45 in 2016, 42 in 2017, 37 in 2018, 38 in 2019, 37 in 2020