To Set Up Grid Units

Open the Design File Settings dialog ( File > Settings > File > Design File Settings ).
In the Category list box, select Grid.
Controls for adjusting grid unit settings are displayed.
In the Grid Master field, enter the distance (in Working units) between points in the grid.
In the Grid Reference field, enter the maximum number of reference lines desired between grid references.
From the Grid Configuration option menu, select an option.
In the Grid Aspect field, type the ratio of the distance between the grid points along the design x-axis and the distance between grid points along the y-axis.
In the Isometric configuration, this ratio is fixed.
From the Orientation option menu, select ACS, Top, or View (plus, in 3D, Front and Right).
Click OK.