Some advice for if you’re having trouble drawing hands proportionally, for basic pictures–
Put your own hand on your face, with the heel of your palm on your chin. Pay attention to the overall width, and where your fingertips and knuckles are.
Then draw a rough outline of the hand over the face you’re drawing, and match the proportions to yours. You can adjust up or down a bit from there if you feel the need, but that should be a good base visual.