The #editor will let you use one of three different styles of markup, which you must define using the dropdown box in the top right of the content window; legacy, html and markdown.

The content edit view with 'Markdown' selected in the top-right

The content edit view with 'Markdown' selected in the top-right

The three choices of editing syntax: markdown, html and legacy (rich text)

The three choices of editing syntax: markdown, html and legacy (rich text)