The My Courses widget lists courses that you have been enrolled in.
Most courses will show in your course list starting on the published start day and start time per your schedule. Some courses may show sooner if the instructor of the course has chosen to release the course prior to the published day and time.
Most courses will no longer show on your course list after midnight of the seventh day after the published end day per your schedule. Some courses may show later if the instructor of the course has chosen to end the course after the published day and time.