I think the 788 only has a digital IN, not OUT. You can take the audio straight out of the Stereo outputs into your sound card. But the best way is to export the WAV files to CD and then into your computer. I'm assuming you have the CD-Burner. That's your best bet.
Whatever, you do, DO NOT try to hook up the 788's SCSI to your computer, you'll probably seriously damge both.