...
You will now be able to select the chart type that you want to use in the drill down level from the Chart screen and add the data that you want to see in that drill down level. For more information on creating Drill Down Levels, please refer to this section in Getting to Know pi.
In the following example, the first drill down level contains a bar chart that shows the Cap Colour and Mushroom Count.
...
For more information on creating and using drill down levels, please refer to this section in pi LearnDocumentation.