I understand, but if you look closely, you`ll never see for example that the contour of a leg are two "S" curves or two "C" curves, if you look closely to a leg, it's easy to visualize all the little bumps created by muscle, bones, tendons and fat (it is easy to get lost in all that detail). But when drawing the gesture, we are purposely ignoring all those details and drawing just simple major lines that connect those forms. Perhaps it sounds too abstract now, but I would encourage you to keep practicing gesture because after putting it into practice for a while it becomes easier to grasp.