How do you defeat ganondorf?

Well i hope you are talking about Ocarina Of Time! If so i can help. In stage 1 of the fight, Ganondorf is going to be shooting balls of electricity at you. Make sure you have your Master SWord equipted and hit the ball of electricity back at him. Do this until it hits him, then take out your Bow and arrow and shoot him with a light arrow, then go hit him with your Master SWord. Repeat this process until you beat him. Then he is going to try to crush you in his caste with his last breath, just follow Zelda out of the castle. Then in stage 3 he is going to use the triforce of power to turn himself into a huge beast. He is going to knock the Master SWord from your hands, so just equipt the Biggorons sWord after. Now just run up to him, and when he goes to hit you run/roll between his legs and hit his tail. Repeat the process until you have weakened him and it allows you to get the Master SWord. Now to beat him faster you can hit him in the head with a light arrow that will stun him, then run behind him and strike him in the tail with your Master SWord. Repeat process until Ganondorf is finally defeaten. Hope i helped and good luck!