Showing and hiding grid lines
You can use grid lines to guide you when repositioning or resizing photos and videos. You can also use grid lines to line up titles in your movie.
To show grid lines1 In the Edit workspace, double-click a clip to display the Options panel.
2 Click the Edit tab.
3 Check Show grid lines.
Click the Grid line options button 
to adjust grid line settings.
to adjust grid line settings.