Ok. So I am going to go through the combo in this deck, and how to use it to get a turn 3-4 win.
Fauna Shaman/Survival of the Fittest - These cards serve the exact same purpose; to get Emrakul, the Aeons Torn into your hand. Simply sacrifice an elf, and Emrakul is in your hand in a flash.
Elvish Piper/Norwood Priestess - These cards are the second part of the combo. They get Emrakul onto the battlefield without you having to pay 15 mana.
Emrakul, the Aeons Torn - Obviously the star of the deck, when to your opponent's surprise, you get him onto the battlefield on turn 2, 3, or 4.
USING THE COMBO:
While this is not the only situation, I find it to be the most common one while I was playtesting.
Turn 1: Play a forest. Tap to play a mana producing elf such.
Turn 2: Play a forest. Tap both forests to play either Survival of the Fittest or Fauna Shaman. Use the mana from the elf to play another mana producing elf.
Turn 3: Play a forest. Tap three forests and an elf to play either Elvish Piper, or Norwood Priestess. Activate their ability (using the mana from the other elf if necessary) to play Emrakul, the Aeons Torn
Turn 4: Now you can do whatever you want, but my favorite move is playing a forest, then an elf, and then Overwhelming Stampede.
Feel free to comment to give me feedback as this is only a rough copy. +1s are appreciated if you liked, and thanks for checking out my deck!