The WDH bars are much easier to install if you jack up the hitch. So, you will back up to the hitch, lower the hitch onto the ball, latch it, jack up the hitch ( lifting the suspension at the rear of the tow vehicle ), install the bars, hook up the chains from the bars to trailer frame and lower the hitch all the way.
When unhitching, you want to be straight and level. You will jack up the hitch, lifting the rear of the tow vehicle, unhook the bars, lower the hitch, unlatch it, raise the hitch off the ball, drive the tow vehicle forward and then lower or raise the hitch to level the trailer.
I unhooked once with the trailer on my slightly sloped driveway and the tow on the road. I used the provided pipe to unhook the chains and the force drove the pipe into my driveway. I'm very glad my foot wasn't in the way.