Whilst viewing a page within the knowledge base, select the 'Add to book' button on the toolbar located on the right.

A toolbar named 'Book creator' should appear at the top of the page, with the current page being viewed added to your selection.

If you open up a different page within the knowledge base, the 'Add this page to your book' option should appear in the Book creator toolbar. Clicking on this will add that page and its contents to your selection.

In the Book creator toolbar, clicking on 'Show, modify book' will bring you to a new view where you can see all the pages that have been selected for your book.

To remove pages from your selection, click on the trash icon beside the page name. A list of all removed pages will be displayed under 'Pages removed from selection'.

To rearrange the order of pages, hold click on the page name and you can move pages up and down via drag and drop.

In the 'Show, modify book' view you can give the book a title and choose the desired output format and download your book under 'Export selection'.

Also you can save your selection of pages under 'Save selection' to use for unfinished/future books.