Original: Before dying, the Great Deku Tree gives Link the spiritual stone of the forest, the Kokiri's Emerald, and sends him to Hyrule Castle to speak with the princess of destiny, Zelda.
Simplified: Before the Great Deku Tree dies, he gives Link the Kokiri Emerald, a magic stone, and tells him that it was a man in black armor who put the curse on him. He also tells Link that he needs to go to Princess Zelda of Hyrule at Hyrule Castle.