chapter hierarchy

[seite7]

I started to create my first book, but after reading the documentation and playing around with it, I still can't figure out how to create a chapter hierarchy.
The documentation page has main chapters (1, 2, 3 ...) and sub chapters (1.1, 1.2, 1.3 ...). How do I do that? From the article page I just seem to have the option to add the page as chapter to the book itself, making it a new top level chapter.

[pegasus]

To do this, the chapters must also be created as books. You can move them to your Book forum if you need to. You then add the (chapter) books into your main book.