I'm fairly new to them myself. Water when wrinkly (about once every few months)- lithops will rot away quickly if overwatered. When splitting, like 3 of mine are, do not water at all. In terms of substrate, it must have very little organic matter. Mine are in entirely perlite with exception to some small amount of soil near the roots. In terms of light, they need 12-14 hours of full sun, or full-spectrum light if using grow lights (like I do). Lastly, be patient. They grow slowly and go at their own pace.