First, you need to find a workstation on which accounts have been provided for your course. Your instructor should tell you which room(s) to go to, or check the public notices on the first floor of the Computer Science building. If your course is not assigned to the Unix workstations, you should log in on a Windows XP workstation elsewhere in the building.
Find the room where you are supposed to do your classwork, then find a computer that is not in use. The login serves two roles: the banner identifies the hostname of the computer you are using; the login prompt provides authenticated access to the computer. Your login name is the unique name by which you are publicly known to the system. This name is usually just your first or last name, or some combination thereof.