Course instructors and administrators are responsible for adding students to their courses and sites. If a course or site does not show up when you login to SOLE then it is possible that the you have not been added to the list of users for the course/site. If you believe you are missing a course you can use SOLE Help to make an inquiry:
The course administrator is not necessarily the course instructor; you may also want to contact your instructor. It is also possible that you have been added to the course/site but that it has been hidden from your homepage list of Courses & Sites.