Most materials held by libraries on university campuses will be available to you in open stacks. This means that once you locate an item using the library catalog, you will be able to go to the stacks (or shelves) yourself to take a look.
There will also be items held in storage either in a special location in the library, somewhere else on campus, or off-campus that you may request using a paging system. These are often older, rare or seldom used items.
Borrow a Book, DVD, etc.:
If you want to check-out a book or other library materials, you would then take it to the circulation desk. If you need help locating an item, you may ask at a service desk (often called a reference or circulation or information desk).
The two main classification systems used by university libraries in the U.S. are:
You might also find a library with its own classification system for some portion of the collection - especially for non-print media or older titles. Ask at a service desk if you need help with finding the materials you're interested in viewing.