You can find materials that your instructor has put on reserve at the reference desk in the library. Make sure you know the class and instructor's name to get the materials. Items put on reserve are for in-library use only.
You can search for the book title, instructor's name, or course name in the course reserves.
The Texas A&M University-San Antonio Library usually does not have textbooks, but you can search for the book title in the course reserves. Often textbooks have more than one edition, so you may want to check the publication year of the book you need.