Hey,
I don't know what daw your using and if this will work for you.
I have selected my 16x08 as my main playback device in Windows. I use FL Studio and select Primary Sound Driver. this way I can have both sound in the DAW as in windows and internet and stuff.
Another way is to use a stereo mini jack to 2 male mono jack cable. you select your standard sound card in Windows and use the cable from the headphone of line out from your computer to your line ins on your 16x08. Make sure you have monitoring on.