Pages may be duplicated in the book manager. Check Out your book before managing any structural aspect of it. Book check out is required to ensure that page order, page deletion and portrait page updates will not negatively affect the work of other team members.
To duplicate a page...
Click on the ... icon on the top right corner of the page.
A copy of the page will appear following the selected page.
Once you have completed duplicating the page, Check In the book so that your team members can continue working on the book.