help converting itunes music to WAV file using CDex

I want to convert itunes music to a WAV file to use in a youtube video but i dont know how to use CDex. it wont let me add any music to the artist search bar.

Many of these tools will not work if the music was purchased with FairPlay® copy protection – as many iTunes songs are. The traditional way around this is to burn a Music CD with iTunes and then use CDex to rip the CD. You can also use the Self-Recording feature of your machine to record on Audacity.