How can I make a scene like live demo Island on u3d web?

I mean stream and display a basic scenes and countinue to download 1% - 99% and then after all is downloaded show the full scene. My question is that is there an example that show me how to do exactly like the live demo Island ?
yes I already know we should use assetbundle, but how to do that exactly.Is there an example about this topic? thankyou very much for your reply!

Well when I got Unity, it came with the Island Demo. So I figure everything that you see in the demo should be the answers for your question.