Guide
From SAP Enable Now Wiki
Scope
Purpose
A guide is a layout object that can be used for aligning other objects on the Book Page (objects will snap to the center point of Guides. Guides are not displayed in the Book Reader.
Guides are defined for a Book Page, not a Book, which means that they need to be assigned to each Book Page individually - although they can be defined in a Template, and will then be present on all Book Pages created from that Template. Guides can be copied/pasted from one Book Page to another.