When you have selected a Report category and the particular type of Report (details can be found in other Report articles), further options will appear as in the below screenshot, allowing you to filter the output in multiple ways.
Once you have selected the filter options you require, clicking on "View Report" will make the report appear below the Options box. If you make changes, you need to click "View Report" again for the Report below to reflect the changes. You can also click on "Save / Email Options" to save favourite report types or update email preferences (such as telling the system to email you a certain report every day for the next week). The "Download" button allows for PDF and CSV files of the report to be saved to your computer/device.