"not connected to computer but it is powered" this situation is so called stand-alone-mode.
The user manual describes this in many details.
One detail important for you, in standalone the Adat is reduced to only the first two channels, 1/2.
You can use the buttons on the Babyface to make the routing.
From page 90 user manual :
The input signals can be routed/mixed to the outputs by activating the unit’s Mix mode:
Use OUT to select the desired output
Use IN to select the input with the desired signal source
Push MIX. The input LEDs start to flash.
Use SELECT to choose between left, right or both input channels
Turn the big knob to set the actual monitoring/routing level
Continue with all inputs and outputs as you wish
M1-Sequoia, Madiface Pro, Digiface USB, Babyface silver and blue