After talking with Baquo, Macbeth starts to hallucinate and the first thing he sees is a dagger pointed directly at him.
HOORAH I AM THE KING. THE WITCHES WERE RIGHT>
You did something i just know you did.
After seeing the dagger, Macbeth kills King Duncan. After killing the king he hears some of the servant saying things that are making Macbeth nervous.
Macbeth leaves the scene to talk to lady Macbeth, to tell her that he has killed the king, but he has mismanaged the situation. While talking Macduff comes to the castle to be at the Kings command but realizes he is dead.
Macbeth is now the new king of the land but Macduff did not attend the coronation because he is suspicious of Macbeth and so is banquo