How could I recreate this setup?

[Yuiii]

Hi,

 

I have seen a video by DIY Perks that shows how he made an external control hub for his computer. Immediately, I was interested and began to plan my own. I really liked how he had set up the audio but I am unable to figure out how he managed to make it work. Basically, different combinations of the three ports result in different combinations of devices being used to play the audio. He will do a much better job at explaining it than I ever could so please see the link below to see a good explanation of what it does.

 

If the video starts from the start, just go to 4:56 to see what he has to do.

Thanks for any help, 

 

~Jaffa~

[Yuiii]

No idea then?