How do I use this?

Umm, I don’t quite get how exactly to use this website. Is it only for playing or can I write music too? If I can, is there a tutorial anywhere I can refer to?

Those are really great questions, welcome!

Is it only for playing or can I write music too?

There’s no recording yet, so right now it’s basically just an instrument. Follow for updates and contribute your ideas on Recording to MP3/WAV/OGG and Recording -- MIDI file output. Recording of some form is coming soon.

If I can, is there a tutorial anywhere I can refer to?

There isn’t but there should be. I’m going to work on getting a basic tutorial/help section up so the full set of features are documented.