It's pretty simple really; interlibrary loan is where if we don't have the book or article you want, we'll get it for you from some other library. You don't have to worry about what library has it, just ask for what you want, and if it's available we will get it to you. Public and school libraries don't do as much of this sort of thing, but it's a staple task for college libraries, so you're not asking for a special service. There's a link for interlibrary loan on the LITS home page, links in the databases etc.
It doesn't take too long, usually 2-3 days. Articles get emailed to you as attachments, books you come in and pick up in the library. There isn't normally any charge or fee. If there ever were, or for some reason we cannot get the item you want, we contact you and suggest what the options are.