/ic/ - Artwork/Critique

hello. I started past month I am having problems with the box method
I am reading hampton and the problems I am having (the ones I can notice myself): I don't have any idea regarding the thickness of the arm/leg, I don't know where in the box the leg cylinder is inserted, I also have problems connecting the ribcage with the pelvis. my external oblique doesn't look natural at all (should've taken a pic with him boxed, sorry)

also, I googled and there are a few pics of how much the spine can rotate/bend/move, is there any rule to follow regarding that?

I'm doing the box method to practice perspective because a brazilian youtuber said it also teaches me some important concepts while I am practicing figure drawing

also, is my eraser atrocious or am I retarded?