Courses that show up on the home page of myCourses are pinned. Here's how you can find your current courses and pin the one's you want to your home page.
The orange number following the course title is a number reflecting the total of the following updates in a course.
Unread Discussion Posts
Ungraded Quiz Attempts
Unread Dropbox Submissions
When you visit the course, the Updates widget breaks out the updates for easy access. On the default course homepage, the Updates widget is found at the top of the right-hand column.
The top navigation bar has a course selector icon which allows access to courses and a course search across most pages in myCourses.
Course selector icon