I built my first gaming PC a few years ago. From what I've heard, you don't need to buy a soundcard unless you're a serious audiophile and have the sound system/high end headphones to notice the difference. So you should be fine with the drivers that come with your motherboard. The entire process took me maybe 8 or so hours; it was surprisingly a lot of fun and I don't regret building it myself one bit. I relied heavily on this Tested.com video where Will and Norm build Jeff a PC. That video is pretty outdated by now and they've put out a new one earlier this year.