watering rockwool

Im new to cloning so i decided to take the simplest route. Im simply buying a tray and a 6'' humidity dome, and ill keep the cuttings in rockwool. But my question is how often do i need to water the rockwool?

Just squeeze out the water so the rockwool is still damp, you don't want it soaking wet or dry. I'd put it in reservoir of about 1/4" of water, and keep it that way until it roots.