Click on New +
You must first select a manual, then you can create a new chapter.
Include a title
A chapter title should be fairly broad. For example, if your manual is titled Managers, a chapter title might be something like Reports. Then, underneath the chapter, you could create articles that answer common questions about reports.
Publish a chapter by clicking on the dropdown
When you first create a chapter, it is unpublished. You can publish it (along with other edits) by clicking on the action menu.