Which owner's manual? The one that came with the coach or the crowd sourced one found here:
Your Axis already has a spot to hook a hose to so the pump can source the antifreeze straight from the jug. Find your water pump and follow the intake line. You'll find a T with a line going to the water tank through a valve and another line that ends with a cap.
Remove the cap, hook up a hose, close the valve. Put the other end of the hose in your antifreeze jug.
Don't forget to open a faucet when you turn the pump on--nothing will work with a closed system.