(From page 14 of the Command 8 Guide)
To enable Command|8 in Pro Tools:

1. Make sure your computer, Pro Tools hardware,
and Command|8 are powered on and operating
correctly.
2. Launch Pro Tools.
3. Under the Setup menu choose > Peripherals and open the
MIDI Controllers window.
4. Choose Command|8 from the Type pop-up
menu.
5. Choose C|8 Surface (Windows) or Port 1 (Mac-
intosh) in the Receive From and Send To selec-
tors.
6. Hit OK and close out. The Command 8 should come online.