When editing your report, click on the Charts tab to create a pivot table.
You will be taken to the Charts screen. Click on the switch to turn the Chart Report on.
Click on the Create New Chart button.
Choose Pivot Table from the chart options available, Save and Run Report.
Drag and drop the relevant fields into the Pivot Configuration. Click on the word Sum in the values field to change the value.
Click Save to view your Pivot Table.