Inside Hyrule Castle
This dungeon is pretty straightforward, but it still has some tricks up its sleeve. Head right through the opening chamber into the second room where a Ball and Chain Soldier awaits. Be careful of his weapon of his choice, but a few strikes will take him down. Proceed to the next room.
Take out the soldiers and head up the stairs to the second floor. The floor up here is packed with more soldiers. Take them out to open the door on the left side of the room.
Head through to find a hallway lined with inactive Armos. As you approach the next door, they will wake up in waves. Take them all out to open the way forward.
The last room on this floor is simply a balcony leading to the next level. Continue forward.
On the fourth floor, you'll encounter Yuga and Zelda. After the cut scene, Yuga will spawn some Soldiers. Take them out, and chase him up the next floor.
Take out the Soldiers and head for the door at the southern end of the room. Cross the balcony and head through the door to other side of the previous room. Head to the next set of stairs to reach floor six.
Head through the winding path here, taking out Soldiers as you go. When exit to the balcony, head through the northern door to return to a part of the previous room you couldn't reach. Head up the stairs here to floor seven.
This floor is just an inner room and balcony. Head out side and take the steps to reach the boss chamber.
Yuga hasn't improved much since your last encounter. He'll merge into the wall and split into some copies, but the real one has a glow to his staff. A few sword strikes will teach him his lesson, ending the fight quickly.