Start by talking to Celeborn. He is in one of the tree houses. He will tell you that a strange creature (Gollum) has been seen in the woods. If you see Gollum, he will give you a reward. If you find an Elf in the woods, you can pay him a coin and he will play a tune (low note, high note, medium note, high note, low note). After that, go west to find some musical stumps. An Elf that has been blocking a ladder will now move. Next, go west, then north. When you enter to the north, you will see Gollum running around by a stream. Return to Celeborn and tell him the creature is Gollum. He will give you the Bow of Galadriel.