Use the Grid Settings command to specify the spacing and color for the grid used with the Snap to Grid and Show Grid commands.

Enter the desired Horizontal and Vertical spacing for the grid. You can change the unit of measurement (pixels, inches, centimeters or points) used to specify the spacing, by clicking on the measurement indicator to the right of the size fields.

You also may specify a Color for the optional visible grid which can be activated by enabling the Show Grid option.  Select a color that contrasts with the contents of your picture so that the grid will be easily visible. When the Snap to Grid option is enabled, the mouse cursor to snap to the nearest point on the grid when using most drawing tools.

Check the Default option to apply your grid settings to all future pictures. The next time you open a picture, its grid will automatically use these settings. If you do not check the Default option, only the current picture's grid will be affected.