I disconnect the input to the water pump and connect a hose and insert the other end into the AF. The connection at the water pump is smaller than a garden hose. I picked up a length of clear pipe, and the appropriate connector at an RV shop. After releasing the low point drains to clear out the water, I close them and turn on the water pump which pulls AF into the lines.
I don't use anti freeze. I got a air compressor and hook a hose to the water connection and open the hot water heater blow 50 psi through until all water is out. Open all faucets. I have never had a problem.