You have three primary sources of the music and sounds from which you will build your iTunes Library:
Audio CDsYou can add music from your audio CDs to the iTunes Library. In iTunes lingo, this process is called importing.
Note
iTunes uses a more civilized term (importing) for the process of converting an audio CD into a different format and adding the resulting music to your Library. The more traditional term for converting audio CD music into the MP3 format is ripping. I kind of like ripping myself, but because importing is the term iTunes uses, I guess we will go with that.
The InternetYou can download music and other audio files from the Internet and add those files to your iTunes Library.
The iTunes Music StorePart III of this book, titled "The iTunes Music Store," is dedicated to this music source, and for good reason. Using the iTunes Music Store, you can search for, preview, and purchase music online and add that music to your Library.