Escaping the Castle:
After defeating Ganondorf, you'll have a timed escape sequence with Zelda. Follow her through the collapsing castle, avoiding falling debris and enemies. Once outside, you'll face the true form of the King of Evil.
Ganon, the King of Evil:
This is the final battle. Ganon is a massive beast. Your primary strategy is to use the Light Arrows to stun him, then attack his tail with the Master Sword. When the Master Sword is knocked away, use the Megaton Hammer or Biggoron's Sword until you retrieve it. The Sages will assist you in the final blow. Congratulations, Hero of Time!