Assuming you're streaming from a home network, unless you have enterprise-class gear, I wouldn't trust QoS to even work right, even if it was listed as a feature on your home internet router. If you did have enterprise-class routers/switches at your home, then you'll need to have the knowledge to set them up, which I think is out of scope for these forums. In order to get any positive effect out of QoS, something else on your network will have to feel a negative effect. It would be better for you to determine what else is using your bandwidth and get rid of it than trying to reserve bandwidth for OBS through QoS policies.
Furthermore, without QoS your internal network gear will give all your network traffic its best effort to navigate your network. Unless you have gear from 15 years ago and you're doing massive file transfers all the time, you're probably not maxing out that gear. And no QoS policy is going to make your stream travel through your ISP faster; once it leaves your network, you can't influence its priority. The point being, unless you're maxing out your routers and switches, even a properly configured QoS policy won't be triggered to take effect. So QoS will do nothing good for you, it'll solve no problems, and you don't need it.
On the other hand, if you're in a corporate environment, whoever your IT/networking people are should be able to answer your questions.
Now, in case you're determined to do something silly, here's a link to some "light reading":
http://www.cisco.com/en/US/products/ps6 ... _home.html