I can see my course but I cannot access it

You may not be able to access your course for a few reasons:

In general, courses are not available until the first day of term so you may see the course under future enrollments but it isn't accessible.

Your instructor may have chosen to not make the course available on the first day of classes in which case you would see it under future enrollments, but it wouldn't be accessible. You should check with your instructor as to when it will be available.