'Go study anatomy' is rather a useless thing to be told if you don't already have been doing so and know how to go about doing it (or if you have a method of going about studying that works for you) or if you are just starting and have no idea how to do so. There's so so much, it's overwhelming. If you ever do develop a curiosity for it, then know that anatomy isn't this strict guide of proportions. Anatomy isn't 'the human body is #___ heads tall', 'the pelvis is at the center', and it certainly isn't drawing the contours over and over again. In going for actual and/or idealized figures, sure, those head unit proportions are important to reach. But in starting to learn, your goal is to find out why a certain line is drawn in a certain place or why this curve is drawn like that. Head unit proportions doesn't teach you that, and neither does contour. So I recommend if you want to study sometime in the future, that you first learn the skeleton. It is literally what the entire body is framed around. Then after you learn how the skeleton looks like--and this can just be a general overview of it, just this much will already help you in your drawings--take small portions of the body at a time. By small portions, I mean like head, upper arms, upper body, thighs, pelvis, shoulders, neck, head, take just one of those sections and see how the muscles attach underneath (and maybe learn those bones in slightly more detail if it either interests you or if it's needed to attach the muscles). It doesn't help me to simply look at anatomical diagrams, so I usually google multiple results of 'how to draw ________' and 'anatomy for artists' and cross-check, because those boil down the muscles into the ones that are relevant as far as drawing is concerned. Muscles connect the bones together, they literally stitch the body together, into one whole being. Usually there's only around 5 or so big muscle groups per section but once you start drawing those, the contours and figure just draws itself. The skeleton will teach you proportions and the muscles will teach you the shape of the body, in any angle.
Well this place is fairly lethargic, but mostly because not many people are posting stuff. When they do, then it seems people check often enough that they post replies. So I hope you stick around, AAA can always use more (active /notme) company.