You can add your own songs for piano as MusicXML files. You can either create MusicXML files yourself with any notation program or search them on the internet.
Adding songs is very easy. Here is how to upload them:
Go to "songs" tab and press "+"
Click on "Import File"
Browse for your MusicXML-file
Choose the track you want to play
You can play the song and save it after that.
Press save and that's it!
Supported MusicXML files: .xml, .mxl (compressed music .xml)
(requests "download", "upload", "downloading songs", "uploading songs", "uploading" are redirected here)