The Grid is an alignment aid. You can choose to display it by pressing on the Grid toolbar button or use the Options:Grid Visible menu pick. The Options:Grid Size menu item will bring up the following window and allow you to customize the spacing of the Grid:
Use the arrow keys to increase/decrease the current grid size, or simply type in a new value. The Grid size can be set in the range of 5MM to 100MM.
Regardless of whether or not the Grid is visible, you can snap Gauges to it by right clicking on a gauge and selected the Snap to Grid menu item.