Rulers are useful when you need to accurately place layer content or guides in the document view.
To show or hide rulers:
On Toggle Preview Mode's options menu, tap Rulers.
To reposition the spread origin:
Do one of the following:
Drag from the default horizontal/vertical ruler intersection at the top left of the document view and drop on the page to position the spread origin. If snapping is turned on, the spread origin can snap to objects on the page.
On Toggle Preview Mode's options menu, select Guides Settings. Adjust the X and Y values in the Spread Origin section.
