To Dos are the courses that your tutor or manager wants you to complete. They may have set a deadline for completion as well.
Courses you need to complete appear marked as 'to do' at the top of the favourites tab in your course library. They're easily visible when you log in. To Do items that are due soon or are overdue are identified with a warning too. You will receive an email to tell you that your tutor has set you a To Do, and reminder by email one day and one week before the due date.
You can remove a To Do item from your favourites tab by toggling the heart icon in the course details. You cannot remove a To Do entirely - only your tutor or manager can do this.
You tutor or manager can use the online tutor dashboard to check whether you have completed your To Do on time.