Surround Sound depends on the audio interface and control software that you are using to set it up.
For a 5.1 setup you're going to need an audio device with a minimum of 6 outputs.
Front Left / Front Right = Main Out Left - Channel 1 and Main Right Channel 2
Rear Left / Rear Right = Channels 3 and 4
Center / Sub = Channels 5 and 6
However this is all meaningless without the control software to send audio to the surround mix.
If this is for use in surround mixing, then look to your DAW. Studio One does not natively support surround mixing, so you'll need to use a plug-in for this. If you're using another DAW that does offer surround mixing, you'll need to read their user manual on how to set it up in their software.
If this is for a home audio setup, you'll need decoding software that can decode the surround audio signal (AC-3, Dolby 5.1, or DTS) from the DVD / BD send audio to the individual outputs. There are a few companies that offer software that does this. Cyberlink Power DVD, Intervideo WinDVD and there may be others.
Your audio interface must appear in your Windows Playback devices as individual or paired outputs, or this will not work.
Without more information, this is about as far as of an answer that we can provide.
