For all versions of MeasureSquare 8
Step 1: Select the "Legends" icon from the Shape section of the tool bar. A popup will appear to select the products you want listed for this particular legend.
Step 2: Then left click on the desired area to place the legend. You can always move the legend to a new location by left click and holding, to move.
Step 3: To add a Legend with product usage, select the drop down menu from the "Legends" icon and repeat the previous steps.
Note: You can add more than one legend to a diagram, and edit the text features of the legend by double clicking on it. Right click on legend to delete if needed.