"how to draw the head and hands" by andrew loomis is a fantastic starting point for hands :+) "drawing dynamic hands" by burne hogarth is also really good! loomis sets you up with breaking down the general structure & shapes of the hand, whereas hogarth focuses more on anatomy & locomotion.
whatever your skill level, you can never go wrong with loomis! hogarth's stuff is admittedly very dense & advanced, but it's invaluable information all the same. "classic human anatomy in motion" by valerie winslow has a wonderful section on hands, as well.
hope you're having fun drawing :+) hands are easily one of the most challenging parts of the human body to draw, but once you start learning how they work, it all falls into place in due time. soon you'll love to draw them!