simply shakespeare macbeth act 1 - what is the point of the 1st literally and in reference to the whole play

If you mean the 1st scene, then it seems that this scene recounts the witches' plan to "meet with Macbeth" once the battle is over. The witches' oracular words set the stage for the entire play--especially the immortal line: "Fair is foul, and foul is fair / Hover through the fog and filthy air." In plain English, what is good as bad, and vice versa. There is something afoot, to put it shortly.