Open up the web browser of your choice and navigate to a website that contains free text aids. There are a variety of services online that match this description, including Spark Notes, Cliffs Notes and Book Rags. Depending upon the text that you need assistance with, there may or may not be a free text aid available at each site. Though most text aids on these sites are visible online, many can be downloaded and printed out as well.
Go to your campus bookstore or other bookstore in your area. Bookstores often sell text aids that can be purchased inexpensively, some of which are far more robust than those that are found online. If you have difficulty locating the text aid you are looking for, ask whoever is working at the store for assistance.
Ask your professor if he knows where you can find a free text aid for the text you are having difficulty with. Since many texts do not have published study guides that correlate, your professor may have to create one for you. Many schools sell or freely distribute study aids for texts that are part of their curriculum. This is often the only way to gain assistance when a text aid cannot be found online or in a bookstore.