You just don't know enough about the foundations the article is building off of to follow it. What I do in such a case, is forget about the article at hand, and make a list of things that I don't understand and then try and learn about them all individually. It's okay to just bounce off of a technical article and use it as motivation to learn more about the subject from other sources.

For example in this article, I got completely stuck on how the Exp and Log functions he's talking about relate to the usual definitions of those functions, so now I'm going down that rabbit hole.