How to create simple flowcharts
It’s much harder to do than you realize, because Discourse’s “preview panel” (seen on the right side when you are writing a post) causes your text cursor to act buggy, and it will even apply an “auto-resize” which crops out the flowchart. 
In order to make a flowchart, you need to do it “blind”, without a real-time preview. (You have to memorize the syntax and rules.)