Go to Discovery. Choose "Advanced Search" and, in the "Search for" field, select "Course material." To browse all materials, type an asterisk (*) in the search box. You can further limit the results using the facets on the left, such as by "Course Instructor" or "Course Name," or enter these details directly in the search box.
For further assistance, check out the Library YouTube tutorial: Accessing Your MBA Course Readings: A Step-by-Step Guide