Why are my sections numbered 0.1, 0.2, etc instead of 1, 2, etc?
This problem occurs when you are using the report documentclass, and use "sections" as your top level of the hierarchy. In the report class, it expects "chapter"; so, everything is numbered as if it were in "chapter 0", since you don't have a chapter command anywhere.
There are two ways to fix this; either use the article class (which has section as the top level in the hierarchy) or switch all your \sections to \chapters, your \subsections to \sections, and so on.