in what circumstances Macbeth became the king og scotland?

I'll go over the main stuff.

-Three witches profess Macbeth will be Thane of Glamis (which he is) Thane of Cawdor and King.

Meanwhile the Thane of Cawdor is proven to be a traitor and is killed. Duncan (the king) gives the title to Macbeth.

-Now Macbeth thinks the witches were on to something! He thinks about being King.

-With the help of his nasty wife, Macbeth kills King Duncan in his sleep.

-Duncan's two sons Malcolm and Donalbain think people will blame them so they take off to England and Ireland respectively.

-With Duncan's sons out of the picture, Macbeth becomes king and completes the witch's prophecy.