Rulers are useful when you need to accurately place layer content or guides in the document view.
To show or hide rulers:
From the View menu, select Show Rulers. A check mark is displayed next to the menu item when the rulers are visible.
To reposition the spread origin:
Do one of the following:
Drag the spread origin from the horizontal/vertical ruler intersection to position it on the page. If snapping has been activated, the spread origin will be able to snap to objects on the page.
From the View menu, access Guides. Enter X and Y values into the Spread Origin section.
