Autosleeper Broadway ektblp

(Moved from General Chat)

Good evening, we are buying an autosleepers broadway ektblp and being new to motorhomes, campers before,we have a question about the whale water master.it has a square box type fixture at the van end and a tap conector at the other end of the hose. why do we have the box thing at the van end and can we fit this to a flat hose on a reel.do we leave this hose connected to the van at all times? when on a fully serviced pitch?

thanks for your help