Identifying different "blocks" in a model file

I’ve been attempting to write a Noesis import script for the past couple days, but I’ve been running into some issues. I am unable to identify the different “blocks” in the file where different sections (verts, bones, materials, ect) begin. I don’t know if it’s the hex editor I’m using (HexEdit) or me being dumb, but it’s a real pain to navigate around, and I can’t see everything clearly the way I should.