My Passport unused for years...where to begin?

Plugged into laptop…says working. But how do I find out what’s on it…how much available space? etc.

I want to use it with a Yamaha piano.

Depends what your laptop is running. If it’s windows, the drive should appear in Windows Explorer, and be navigable just like any other drive to see what’s on it (and the top level “my computer” view should show its overall size and how much space is currently in use on it).

Under Linux you should have much the same capability with whatever file manager program is favoured in the distro you are using.

found it. Thank you.