To add to do list, click on the Calendar icon present on the top right corner of the header, it will redirect you in the calendar page, here  click on Add icon present at the right side of the page, then enter Title, Date and then click on Save button. Once record is added you can see it in the To Do List.

To edit to do list, click on Edit icon and to delete to do list, click on Delete icon present in the to do list.