A variety of Standard Reports are available, and you can make your own Custom Reports. You can create report categories and put your Custom reports in different categories to get a better overview and to simplify access control.
If you click on the 'Storage time and delay' link, you will see the defined storage time and delay (how 'fresh' reports that should be available), and if statistics are re-generated after midnight. See more details here.
In the Statistics section under Feature guide, you will find information about different reporting levels, how callback is counted and more.
Please note that we plan to let the the new page "Reports (beta)" replace the old "Reports" page late in Q4 2023, so we recommend you start using the new page to get used to it.