Disklavier

I am new to this group and apologize if this has been addressed, but I can't find in in the archive.

I have a DU1-A (upright) with a Mark III DKC-55RCD.

Can someone tell me or point me toward a FAQ that will explain how to connect a Mac and a PC to this unit to play MIDI files.

Specifically, what cable is needed from MacBook Pro (with only USBs out).
What program do you prefer to play the Midi's?  Does ITunes have a 'MIDI out' feature?

I thank everyone for their help.

Scott