You can upload files from PC or import files from Files app to My Files.
Uploading Files
Tap the Upload button to start file uploading service.
Now you can open the service URL in your PC web browser and upload (or download) files in it:
You can do more in the web browser, such as deleting, downloading, creating folders, or even sending a text to your phone!
You can also upload files to it or download its files in iTunes using its file sharing feature.
Import Files
Tap the Import button to import files from Files app and play them.
Please note that files will be copied to our app during playback, so you may want to delete them after playback to save disk space.