This tabs has 2 other tabs.
Edit a chapter in html with the WYSIWYG (What you see is what you get) editor. This interface gives you a series of buttons that can be used to edit your content.
Don’t forget to save when you’re done.
If you’re more comfortable with markdown, you can also use the “update as Markdown” interface of this window.
The code blocks are, by design, uneditable from the interactive mode. This design choice was made for several reasons:
Prevent users from putting html tags inside the code block
If you're comfortable enough writing code, you should be good using the markdown interface :) The first purpose of the interactive mode is to be used by non-tech users.
In this tab, you can:
Add, delete & rename chapters.
Reorder the chapter with a drag'n'drop interface
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.