To create a new Document, open the Project Navigator, select a Book or a Part, and do any of the following:
Open the File Menu > click New > choose Document (or press the ⌥⌘D key combination).
Click the plus icon (➕) beside the Filter at the bottom of the Project Navigator and choose New Document.
Book Summary Page
When a Book is selected in Project Navigator, a Book Summary Page bearing the Book’s title will be displayed.
Click the New Document link beside the space reserved for the Book’s cover image.
Part Summary Page
When a Part is selected in Project Navigator, a Part Summary Page bearing the Part’s title will be displayed.
Click the New Document link beside the space reserved for the Part’s title-page image.
Follows the steps outlined in Importing Text and EPUB Resources.