The Rulers, Grid, Page Dividers, and Snap tools are found on the Page tab.
Rulers are a helpful measuring tool that can help you align and place symbols and objects especially when making floor plans. To show or hide the rulers around your workspace, select or deselect Rulers.
Gridlines help give you visual cues when you're formatting and aligning elements. To show or hide the grid in the workspace, select or deselect Grid.
To see the page breaks in your workspace, select Page Dividers.
To turn snaps on or off, select or deselect Snap. Snaps makes aligning and positioning objects easier. Snaps automatically moves objects to the nearest grid line using the top left edge of a shape for floor plan type diagrams and to the center of the shape for "line draw" diagrams like flowcharts, network diagrams, and software diagrams.