The PixHawk Fire Cape (PXF) is a cape for the BeagleBone Black developed by Philip Rowse. The board is used to support the
AP_HAL_Linux of ardupilot.
This cape contains all the needed sensors to fly. Also contains buses connectors to plug additional hardware you would like: buzzer, GPS, leds, ...
Once the board has booted (and you've logged in, which usually is done using
ssh firstname.lastname@example.org) you should verify that all the sensors are working properly.