This is the best site to figure it out. The fly seems so innocent, but is a challenge to tie well. I love to tie this pattern and it is on my line a ton. You shoud also take a look into Charlie Craven's book for basic fly tying. The RS2 is the second pattern he teaches I believe.
Learning the RS2 was a real stepping stone for me in tyihng flies... Also, I feel that most people do not do a good job tying it correctly. Seeing one of his actual flies in person surprised me.
I wish people wouldn't whore out Colorado waters for the sake of notoriety.