Bookio is a new feature included in your Riffio subscription that allows you to convert your audiobook mp3s into an RSS Feed that can be easily added onto your Storybutton. 

If you can access the mp3 files to your audiobooks, this is how you can make them available on your Storybutton.

For non plan users, Bookio Pro is $3.99/mo. 

For Riffio Plan users, make sure to use the same email address you subscribed with to grant your Bookio account the Pro features.