If you register (takes 2 seconds) there's an example project where you can see the integration steps with the exact code you need to paste in. You're right though, we should definitely add examples to the main site.
I'd recommend not forcing people to register to see generic information like this - I know HN is biased towards "Connect with Facebook to login", I would assume most are also biased towards registering to see content - I know I am.
Ok you guys are right. We're adding this to our site right now.