You’ve completed all the lessons!
If you’d like to know more about using markdown, here are some additional resources:
This is a great overview of all of the things you can do in markdown. It goes into more depth than this tutorial is designed to about all of the options available when using markdown.
http://en.wikipedia.org/wiki/Markdown
For more advanced uses of markdown take a look at this page created by GitHub. This is also a great way to learn what Markdown syntax is available in GitHub.
https://guides.github.com/features/mastering-markdown/
Markdown was originally created by John Gruber. While some of the syntax has changed since its creation the original syntax can be viewed here:
https://daringfireball.net/projects/markdown/basics