What have you read so far? No one is going to just give you the summary you want, you’ll have spend the next few days reading. Summarizing those guys is not easy, especially Nietzsche. Did your prof actually ask you if existentialism is good or bad? In those exact words?
You could start by explaining to your Proff that Camus is not an existentialist, he is an absurdist. Yes, there is a difference.
And no, this isn’t my personal interpretation. If you read the published letters of Camus, there are instances where he says in no uncertain terms “I am not an existentialist.”