“This is a “quick” how-to guide for using Discourse forum/community software. It contains a majority of the common features available to users/content editors, but may not have complete coverage of the feature set. If anyone sees anything to add or correct, feel free to comment. If you’d like to learn more about the Discourse Editor’s syntax take a look at the commonmark (a flavor of markdown) docs for more info.”
I came across this fantastic user reference guide to Discourse post formatting on the DigiKey forums. The text above is an excerpt, and was not written by me. Hopefully it’s okay that I re-post some of it here, as it contains a lot of useful formatting tips. 
Please see An Unofficial Discourse User Reference Guide - TechForum Site and Post Help - Electronic Component and Engineering Solution Forum - TechForum │ DigiKey for the full post, below is a table of contents linking to the specific parts!
Table of Contents