Hi chesterkins,
Normally, to connect a stereo keyboard to a computer, you would use an audio interface that has two identical Line inputs. The Behringer UMC22 is not ideal in this regard, as it only has one combined "Mic/Line" input and one "Instrument" input. However, Line and Instrument inputs have different impedance and sensitivity (possibly even a slightly different sound). The only possibility in your case is to work with two "TS to TS" cables (mono jack plugs on both ends), which you connect to the two inputs (Mic/Line and Instrument). For the reason mentioned above, you may have to set the two Gain controls differently so that both stereo channels are at the same level on the computer.
Note: Do NOT use balanced cables (TRS plugs)!
On the Genos you can either use the Main Outputs (adjustable via the Master Volume control) or the Aux Out sockets if they are set to "Aux Out" in the Line Out display (fixed volume, independent of the Master Volume).
The audio interface is connected to the computer via a USB cable. As far as I know, the driver recommended by Behringer for the audio interface must be installed under Windows.
If required, you can connect your studio monitor speakers to the Output sockets of the audio interface.
Hope this helps!
Best regards,
Chris