There are two main ways to get to your courses
The side bar:
Open the side bar by clicking the W
Select courses
Choose the course you would like to view
This will open the course page
From the activity, using the workbook drop down menu:
Select the current workbook you are viewing
Choose workbooks home
This will take you back to the course page for the current course you are viewing
To view a different course, follow the steps above and choose the course from your side bar.