The report represents usage of the Office 365 applications. In it, you can see several different views representing different datasets of information.
The pie represents the time spent in each application out of all the time spent in the Office applications. Place your mouse cursor over each slice of the pie to see the time in minutes.
The bar chart
The bar chart represents the different segments of users.
The top layer (brightest green) represents the users who were just using the application for reading purposes (no editing at all)
The mid layer (dark green) represents the users who are light editors.
The lower layer (red) represents the heavy users.
The table lets you drill in to see the actual data that stands behind all the charts. You can click on each one if the rows to expand it and see the contents of the data per application.