Now that you have the Kokiri Emerald, it's time to visit Princess Zelda. The bridge that leads to the field is located directly across from the trail leading to the Deku Tree. On your way out, Saria stops you and she gives you the Fairy Ocarina. Before you can actually cross the field, an owl, who I think is the most annoying character in the game, stops you. Listen to what he has to say, then you can head for the castle. Head straight from where the owl was to get to the castle. It will probably be nighttime when you arrive and the drawbridge will be up. Run around outside in front of the drawbridge and kill the Skeletons that pop up out of the ground. When day breaks, the drawbridge lowers. Enter the Market.