The outputs "should" be accessible from the back of your computer. If your comp. has sound, then chances are it is configured properly.
One of those outputs should be your (desktop) speakers, the other 2 (excluding the Game Port), will be yer line in/ Mic in inputs.
If it's not legibly marked (and sound card manufacturers are no slaves to straightforwardness), it'll not make a whole heap of difference. Just remember to keep the output volume low, incase your input levels are too high, or incase you put the mic into the Line in by mistake.
There's always going to be a bit of messing around with it until you get it right. It's a lot easier than wiring a 64 channel mixer up to it, believe me.