plug it into the city water feed and turn the water pump on to suck antifreeze through the lines.
OH - now I see your problem now that I have re-read it. I know exactly what you are talking about in the Jayco book -- I dont know why that is in there like that....but it is wrong.
Look under your kitchen cabinet where the pump is located and you should find a section of clear hose lying there -- that is the hose it is talking about! Switch the valve over at the pump, stick it in the antifreeze and go.
Also - Shurflo says it will not hurt them to run dry, so dont get too concerned if you have to let it run for a while. I know when I purge my system I let it run for quite a while as it spits little bits of water out.