Most people's entire music library is too big to stuff onto the wee Shuffle, but you can Autofill it with a Shuffle-sized serving of tunes. If this is the first time you're plugging your player into the computer, the iPod Setup Assistant appears. Leave the "Automatically choose songs..." checkbox turned on, click Done, and presto: iTunes grabs a collection of songs from your library and copies them onto your Shuffle. After that, each time you connect your tiny Pod, a small panel appears at the bottom of iTunes, inviting you to fill up your iPod with the click of the Autofill button.
iTunes can snag songs from your entire library or just a particular playlist (see Chapter 6); you can also opt to have iTunes select highly rated songs more often. ("Ratings?" you say? Check out Chapter 5 for the details.)
The Autofill box also has a setting called "Choose items randomly." Turning this checkbox on means iTunes moves over songs in whatever order it feels like, instead of transferring them in the same order they appear in the iTunes Library or a selected playlist.
Once you've Autofilled for the first time and then return for another batch of songs, you can turn on the checkbox next to "Replace all items when Autofilling" to have iTunes wipe the first batch of songs off the Shuffle and substitute new tracks.
Once iTunes has filled up the Shuffle, you'll see the "iPod sync is complete" message at the top of iTunes. Click the Eject button next to your Shuffle's icon, and then unplug the player from the computer.