This may help you get started.
Controlling Your Robot: USB HID/Wireless Keyboards - Pimoroni Yarr-niversity
You’ll have to adapt it somewhat. Set the keybow buttons up to send specific key presses, then set the Unicorn / Pi up to look for and act on those key presses.
I tried something similar with mixed results.
Use a media keyboard with your pHat Beat, can it be done? - Support - Pimoroni Buccaneers