Your capabilities in a course are determined by your tier of service at the time you enroll in the course.
If you are currently visiting the site as a guest, which means you have not logged in or you have logged in as guest, you can enter some but not all of the courses in the site. You can enter any course whose title has T1 in parentheses, but because you
are only in the guest tier you may not be able to access all the activities in the course.
If you have a free Observer account, you can access content up to T2, which means you can enroll in any course whose title begins with T1 or T2 in parentheses. Once enrolled in the course you won't be able to access any sections or activities that are
labeled T3 or higher.
You can enroll in any course whose title begins with T1 T2 or T3 in parentheses.
You can enroll in any course whose title begins with T1 T2 or T3 or T4 in parentheses.
Most course allow self enrollment, which means you can enroll yourself whenever you want, but in some cases you will need an enrollment key.
When you see the course in a category list you will see a button to enter the course. Click on the button and you'll be taken to the enrollment options page for that course. Normally you'll see a set of possible self-enrollment tiers and only one will
include an "enroll me" button. The one with the "enroll me" button is the one that matches your tier of service, so it's possible that none of the enrollment tiers are available.
For example, the following is a screen shot of what you might see if you are an active member. Note that only the active enrollment is available.
Near the upper right under "Course Administration" you'll see a link to unenroll yourself from a course. If you ever change your tier of service you'll be automatically unenrolled from all your courses, so if you have any quizzes in progress or stored
material all that information will be erased. This is generally more of an issue with downgrading rather than upgrading. If you have any questions about that email us and we'll do our best to accommodate you.
The "My Courses" link in the bottom menus will take you to a list of the courses in which you're currently enrolled.