Display MoreThe audio interface should be connected to your PC with USB.
I think the confusion is based on what you're calling "computer audio".
There are 2 audio cards in your (and my) set-ups. One is your Windows audio driver and the other is your Behringer.
In order to hear your guitar (in the Behringer) and Windows media like Media Player or Youtube (PC audio driver) at the same time you need to feed the headphone out from your PC into a stereo input on the Behringer. Then they're both in the same output.
This is why I run a small mixer and run my headphones off that.
Wouldn't the computer audio be routing out the USB to the Behringer? That is what I had imagined. And then the Kemper main outs would go to two inputs on the Behringer. Your way would work too for sure, but needs more wires.
Maybe I'm nuts...