When you add or modify a report the "Modify Report" window is displayed. This can also be referred to as the Report Properties window.
There are a number of tabs available on the left of this window which are where the report style and filtering parameters are specified.
There is a Knowledge Base article for each of the available tabs which will explain how the settings are used by Akixi reports.
For a detailed explanation on the report, properties press the F1 key from the Akixi reporting screen and go to section 21 - Report Properties.