After you have added courses to your calendar you may want to delete them again. This tutorial describes how to do this.
Go to: > Calender
Select in the menu of the homepage 'Calendar', and click on the button 'MYTIMETABLE'.
Now click on the button with the three dots behind the course you want to delete from your calendar, and click on 'Delete'. At the bottom of the screen you will be notified that the subscription has been successfully deleted.