Step 2: Change the Grid Size

On a PC, go to the Edit menu in the menu bar and choose Preferences, then

choose Guides, Grid, & Slices. On a Mac, go to the Photoshop menu, choose

Preferences, then choose Guides, Grid, & Slices.

This opens the dialog box to set the Guides, Grid, and Slices options.

In the Grid section, set the Gridline Every option to 2.5 percent. Leave everything else

as their defaults and click OK.