The Courses page lists all courses available in your organisation.
Click on a course to visit the Course Details page for that course, where you can find more information and get started.
The All tab shows the courses you're enrolled in, as well as other courses that are available for free or to purchase.
Clicking on My Courses filters the list to only show the courses you're enrolled in.
The Administration tab is available if you're an Administrator for your organisation, and is where you can create and edit courses.