Hi,
you might want to have a look at https://github.com/moodleuulm/moodle-local_boostcoc/blob/master/lib.php#L91-L144 where we add a node at exactly this location.
Regarding "This link should be available to students", this may be more difficult than you think because the "MyCourses" list is built in system context, but the fact that a user is a student is located in the course contexts. If you can identify any criteria in system context to identify students, you can check this before adding the node to the "MyCourses" list.
Thanks,
Alex