How to assign output channel to VST instruments

I recently purchased Cubase 13 and a Behringer XR18 mixer/audio interface.
Unfortunately when I used Omnisphere (VSTi) it defaults to coming into mixer audio channels 1&2.
How can I re-route to come into the Behringer via USB into audio channels 11 & 12 on my Behringer XR18?
Thanks in advance

Hi Michael and welcome to the forums!

Open Studio > Studio Setup and make sure you have the proper ASIO driver for your device selected under Audio System. Next, select your device which should show up on the left hand side just underneath Audio System. There, make sure you have enabled all the Inputs and Outputs of your choice.
Once that is done, it is recommended that you assign your I/O to Busses in Cubase. To do that, open Studio > Audio Connections and create busses in the Input and Output tabs.
Now you can route your VSTi to any of the busses you just set up from either the Mix Consoles or Inspector.