This is one of many handouts I give to students who are struggling with sculpting techniques. It breaks down the parts of the hand in an easy to digest way.
The biggest mistake students make when sculpting hands is bending the fingers into a curve. As they work, make sure they are bending the fingers at each joint, so that a bent finger creates a rectangle shape.
I hope this is helpful! I've used this with beginning ceramics students with great results. After they sculpt the hands I have them hollow out the bottom near the wrist to help dry them out more thoroughly.