Method 1:

1. Click Group.
2. Click in the Select Column field. A list of columns is available.
3. Select a column.
4. Optionally, click Add Another Group and repeat steps 2 and 3. 

 

Method 2:

1. Hover over the header of a column.
2. Click the three vertical dots that appear to reveal a menu.
3. Select Group by [column name].

 

To view a group's items click the arrow to the left of a group.

To remove all grouping click the X to the right of  Group. 
Alternately, click  Group and click Clear All.