Some library materials are set aside for specific courses. These are called Course Reserves.
The University Libraries no longer host electronic course reserves. Instead, professors may add links or PDFs for electronic resources directly to their Blackboard courses. If your professor told you to access online or electronic Course Reserve materials, these have likely been added to their Blackboard course. However, it’s possible that your professor set aside Physical Course Reserve materials, which can be accessed in person at the campus library.
Please do not hesitate to ask your professor for more direction on where to find your course-required materials. You are also welcome to contact the library staff or to contact your subject-specific librarian for guidance.