How do you properly output 5.1 sound from your computer into a surround sound system for gaming

You need to get your computer to output a 5.1 sound signal to that a receiver can decode it and give you your surround sound. If that's what you're trying to do. Another way would be to purchase a sound card that decodes the 5.1 signal and offers the jacks on the back so that all you have to do is purchase a surround sound speaker set, but make sure it's for computers so that the jacks will be the same, and that way you can cut out the middle man, which would be your receiver.