So, I agree with Joao. Good job on your first attempt. I would pull up a diagram of the muscles of the torso and use that as a way of "finding" where the muscle bundles should go. For example, the pectoralis major muscles connect to the humorous (insertion) and a combination of the sternum and clavicle (origin). Here is a link that shows how all of that goes together (https://www.howtorelief.com/wp-content/uploads/2017/05/Pectoralis-Major.jpg). Look at that diagram and re-assess what you've drawn. Then, try again. You wouldn't believe how many crumpled drawings I've had on my den floor. I think deliberate practice will ultimately win out. Good luck.

When I have attended a real life drawing class, we used to start with really quick sketches where the model was in constant movement. That way we got warmed up and everybodys sketches looked equally bad, and no one worried about it (or we even laughed at each others scibbles). I did classes with real professionals a couple of times, and we all found that part really hard. It's just like warm up before you do some sort of physical exercise or work out - you feel stiff and heavy and sluggish, unmotivated and reluctant, but after the warm up you have loosened up and you feel much more ready for the task. So don't worry about how it looks in the beginning, either single sessions or at the beginning states of your drawing journey. Another tip is to start big. Draw one figure on each page, Size A4 or bigger. That way you learn how to move your arm, you get a better understanding of the general shapes and movements and gestures. If you draw several figures on one page, they tend to merge together, influence and relate to each other, and it can be hard to see the single figures. It's the same thing as with different shades of color; one shade can look completely different, depending on which shade is next to it or around it. Drawing big also helps you learn how to hold the pencil and to draw from your shoulder. When you draw small you tend to draw more from the wrist, which is good for details but not so much when you want to capture the general shapes, gestures and movements. Another one you might want to try is to experiment with having your drawing surface at different angles, to see which one suits you best. Try to make a leaning surface with a board propped up at one end with some books, or something. Try putting your paper on a vertical surface, like a wall, a draw on it like that. Try standing instead of sitting. Find what works for you. =) And one last thing I'd suggest is that you look at your work through a mirror. That way you see it through a different perspective and you can more easily see what's wrong and what's right. (Sorry for the long rant! I hope you found something in there helpful.)