Creating Custom Reports greatly enriches the reporting functionality of the system by giving you the flexibility to control and build on features that are important to you.
To create one, go to Reports > Export > PDF Report. Under Select Report, click the dropdown and select Create Custom Report.
Once you click Custom Report, by default everything is checked and when you run it as is it's going to generate a comprehensive report. To customize the report, click Select None and begin selecting the data by (1) Channel, by (2) Report and by (3) Filter Widget.
Once you have built your custom report, you may either (4) Copy to other projects so you can use the same settings to other projects, (5) Save as template so you can reuse the report at a later time, or (6) Use selected options to immediately apply the settings in the report you are creating.
In the following video, you can see an overview on how to create Custom Reports:
Note that you can also get the raw data by generating an Excel Report.