The Tasks Overdue Today Report can be found under Reports > Tasks Overdue Today.

This report lists your Sisu users and the total number of Tasks assigned to them that are currently overdue.

Overdue Tasks can be individually viewed on the Task Manager:

Task due dates can be easily changed on the Task Manager by clicking the Task then editing the date in the Due Date field:

To edit the way existing Tasks are generating due dates you can refer to this article.

To learn more about creating Tasks refer to this article.