There are two ways to go about it.
#1. Add just enough hot water at the end of the mash to raise the temp to about 165-170F and to make up for grain absorption. Vorlauf and drain that. Infuse one large batch sparge, vorlauf and drain. Done. If you're careful, both runnings volumes would have been close to the same amount and your efficiency is quite high because of it.
#2. At the end of mash, vorlauf and drain (1st runnings). Infuse half the sparge volume, vorlauf and drain (2nd runnings). Infuse last half, vorlauf and drain (3rd runnings). Depending on how much grain you're working with, this can be a very efficient method. I've seen it best the #1 method by 3-5%. In any case, you want the sparge temp to be about 185F so you inch the grain bed temp up.