If you have a multiport attached to your filter that changes from filter, waste, backwash, etc....then all you have to do is submerge your vac, fill the hose with water, insert the other end of the hose into the pipe that pulls from the skimmer, and turn the pump on in "waste" mode. Keep in mind though, that the stuff you're vac'ing up is still going through the pump basket, so if you're vac'ing up a bunch of solid stuff, you may have to stop once in a while to empty that basket out to keep the suction strong.