Click Dashboard

Click Settings

Click Grid Templates

Click + New

Key in the Grid Description

Select the Grid Type from the drop-down list
1 dimension (example: Color)
2 dimension (example: Color/Size)
3 dimension (example: Color/Size/Width)

Select Dimension 1 from the drop-down list

Select Dimension 2 from the drop-down list (If needed)

Select Dimension 3 from the drop-down list (if needed)

Add New Row information that corresponds with the Dimensions (example Red T-Shirt) (Small)

Click Save