After selecting pie chart from chart selection panel, you can configure the chart in right panel.
Following are the details of each field in right panel.
Title of the chart. This can be empty.
Chart data values can be aggregation of some field/module values or simply a count of submissions. This field is required.
Supported aggregation functions are
COUNT returns no of submissions. Other functions require an operand which can be one of the app fields. For more details refer to the example in the last.
Data is grouped by the values of this field. This can be one of the app fields, status, submission creation time, submission modification time. This field is required. For more details refer to the example in the last.