Well, turn the water on and listen for it ;-). Mine is under the passenger side bed on a 2021 Axis 24.1. Yours is different of course.
I just finished our last camping trip of the season, so I fully dumped the black and grey tanks and opened a 1/4 turn white plastic ball valve to dump the fresh water tank. It is very hard to see on mine, but near the water pump there is a plated brass three way valve that you turn to shut off the suction from the now empty water tank and switch it to a suction line where you can suck up antifreeze from a jug.
Thor didn't provide enough hose length to do this (it would have cost them maybe 50 cents) so I will have to get a 1/2" NPT to hose barb fitting so I can attach a longer hose. When I do that I will suck antifreeze up and push it to all of the fixtures.
David
__________________
|