Everyone will give different advice and that's the nature of art because everyone is unique, but as I've learned about things, one thing connects everything and that is depicting form, which requires an understanding of perspective and the ability to create form from imagination. This is where the whole idea of boxes stems from is because of the simple nature and the ability to easily check mistakes in the form of a cube. You can also easily perform cuts to a cube to get new form shapes and slowly start to approximate the thing you want to draw. In essence, you will eventually come to the conclusion that you're basically 3D modelling from scratch. This separation between copying the lines you see and constructing forms that you modify is the big "aha" moment as they are two distinct things. This is why exercises like cutting a person in a reference in half as if they were cut by a laser and having to draw that new form are very useful. I'm replying a bit late to this but hopefully you haven't given up by now. An important thing to keeping your motivation up is ironically keeping your drawing time strict. In the very beginning I limited myself to 2 hours and stopped no matter what, which, if I really was motivated to draw, actually made me super motivated to draw the next day since I couldn't spend all the creative energy all in one go. Insert some philosophy about pacing yourself I guess. Also make sure to use reference even when creating forms from imagination, as that's the only "answer key" you have to find mistakes in the forms you create. Doing things like trying to draw from imagination a pose you've drawn a few days ago is super helpful since you know you can easily pull up the reference for checking what you got wrong. For more tips on being able to construct forms, Scott Robertson's How To Draw has basically everything you need to know to be able to accurately construct forms in 3D space. And investing in multicolored pens or pencils to help keep track of interior vs exterior lines when constructing forms will come in handy. I hope your brain has now made the distinction between 2D copying and 3D drawing and I wish you the best of luck.

The bean is the intersection of the torso + pelvis, or in other words, 2 sphere forms intersecting. You can try finding the minor axis of the ellipse within to check if you are identifying the angle and tilt correctly, draw some ellipse cross contours, or even just trying to draw boxes in perspective on top of the bean to verify that it makes sense. The way the course is setup, it encourages coming back to the earlier lessons with further understanding, so you never really "finish" the basics. As far as I can tell, I think you can move on to the next lesson. Hope that helps.