The handbooks come in separate booklets.
The one you need is the one entitled "Sound System".
Look at the Summary at the front of the book, and you'll find the Menu section.
Mine is on page 15.
If you don't have the books, you can download them
specifically for your vehicle from Fiat.
Go to:
http://aftersales.fiat.com/elum/home.aspx?languageid=2 and input your VIN number. It doesn't seem to work for me if I input my registration number.
You can find your VIN number written on a plate under the carpet in the boot.
The website is slow, but it works. there's a tab at the top of the page where you can select handbooks and supplements.
Good luck,
Mick.