Most of what I know about them I learned from a Murray Carter sharpening video. After soaking them for a bit, he puts his on a folded wet towel on a board over a small tub half filled with water and keeps them well wetted throughout, splashing some more water on them often. He pulls the edges on the stones - similar to stropping, except he uses his fingers to apply a bit of pressure where needed. Being softer and made to wear more quickly, you need to be a bit careful to use the stone's whole surface uniformly.
Also be aware that precisely how you should prepare and use a waterstone can vary quite a bit by brand, binders used, and how fine the grit is - some you soak, some you just splash.