The scene of the 3 witches are having a conversation on where to meet Macbeth or where they 3 witches themselves shall meet each other. And the other mention is the battle.
The main point of this scene is to give an introduction on what the play is and the plain idea and plan of what the play really is about. It is also a great way to grab the audience’s attention, to let them know that the play has started. The witches back in the 14th century