To access historical reports, click on Reports in the left side menu:

From here you can do a bunch of things

The first thing you'll notice is that the different report types is listed in a dropdown menu in the upper left corner:

Select period
You can choose from a selection of predefined periods, or specify a specific period by changing the from and to date:

If you want to add a report, click the button in the top right corner: 

Select the correct type and product, and input all correct values: 

Note that if you have administrator privileges, you will also be able to select which user to add the report for.

One report at the time
To edit one report, simply click the value you want to edit, and it will shift to edit mode:

Confirm the edit by clicking Save changes in the bottom right corner.

Bulk edit
You can also edit several reports at the same time by first selecting them with the checkbox to the left and clicking Edit:

The fields you enable and input a value for will be changed for all selected reports as soon as you click Confirm:

Other fields will stay the same for all selected reports.

Single report:
You can delete a report by clicking the three dots to the right and choose Delete:

Multiple reports:
To delete multiple reports at the same time, select them by clicking the checkboxes to the left and choose Delete selected at the bottom: