I think that's actually the point of dense math formulas/papers like this, but I want to share a resource that helped me start from "ground zero" per-se.

Starting with Mathematical Thinking [1], and adding in practice books for Algebra [2] and Calculus [3] to grok what the different parts of the formulas are trying to capture.

Once I did some basic problems, I found the what and why became much clearer. At this point I tend to read it more as programming code than as archaic formulae.

[1] https://www.coursera.org/learn/mathematical-thinking [2] https://www.amazon.com/gp/product/1453661387 [3] https://www.amazon.com/gp/product/1941691242

(sry for the amz links)