You can use any streaming apps available on your phone. The Neuvana app and your Xen are not limited by any streaming services.
Whenever you are using a music or media source from a site outside of the Neuvana app, first open the media page (media icon) and select External. This tells the app that your music is coming from outside the app.
To choose your music, open your streaming app or online media source, select your music, and adjust your volume.