If you haven't already added a music library to your SoundTouch account, see Adding a music library to SoundTouch for instructions and info on the type of music libraries you can add.
Syncing a music library
Syncing happens automatically in the SoundTouch app. Any changes you make to stored music library content will be reflected in the app within 15 minutes of the change.
If needed, you can manually sync the library by following these steps: