All the help docs deserve the credits:

First post I encountered
Detail installation instructions

Working on the site visit report reminds me about the MikTex tools I had a year ago. And, I am learning it through this process. First of all, there are urls that help me and I would like to acknowledge their effort.

HowToTex is very helpful, but I could not install/use the packages.
This one looks pretty professional.
Math course at Kansas State University is primarily for creating magic math formula.
I started with this dummy skeleton, at least is a working example for dummy.
A self-study manual.
Another LaTex online book here.