When you're not running in a DAW (like Cubase), the Studio 192 and the UC Surface software act like a virtual mixer. All the audio routes to one of the Mix Output Groups in UC Surface. You route everything just like you would on a real mixer.
If you want to use it with a DAW you need to bypass the mixer software (in UC Surface), Studio One does this automatically so the DAW will access the full I/O of the interface so it can be managed by the DAW Audio I/O Setup and it's own routing and mixing system.
All other DAWs this is NOT done automatically, you must bypass the mixer manually before launching your DAW.
In UC Surface, click the Cog Wheel in upper right corner to get to the Setup Page, and click the button "Mixer Bypass"
Now launch your DAW and set up your I/O accordingly the way you've have done it in the past, now your DAW will control the Inputs and Outputs the way you program it too.
When you close your DAW, remember to turn off Mixer Bypass so all your system audio routes out of the Mix Bus in UC Surface.