The best place to learn more about advanced features of Prezi is the Prezi Manual. You'll find links on inserting videos, Flash files, and other figures. There are also a lot more details on grouping objects, using the Themes, creating animation and using 3D backgrounds.
If you are creating a Prezi for a Vanderbilt-related presentation, you might want to consider following the University's style guidelines.
Adding background music or audio to your Prezi is really pretty easy. The first step is to create an audio file (either for your background music, or for your narration). The links in the box on the bottom right offer suggested audio editing tools. Make sure your finished audio file is one of these formats:
When adding music you have two options:
1) Adding a background track (that plays continuously throughout your Prezi) and/or
2) Adding audio to certain steps in your path.
See the link below for more information. Note that this feature is only available for Plus or above accounts (paid).
Third Party Software Applications for Creating Sound
Please note that Prezi is not responsible for the quality of sound files created by any of these applications.