Course Reserves are typically textbooks (sometimes articles) instructor has placed on reserve for you to use.
If you know the title of your textbook, you can search it in the library catalogue: https://www.georgebrown.ca/library-learning-commons
Textbook are either located in kiosks (outside of the library entrance; you need a physical student ID card to open it) or on reserve shelves (behind the library front desk). They can be checked out for 3 hours and cannot be renewed. Please make sure to return them before the due time, otherwise an overdue fine will incur, which is $1 per hour.