Asking question about Carrot and Stick strategy and mulltistage

Question

I am studying Game Theory and I have some confusions.

1. Is actually Carrot and Stick strategy is the same as Grim Trigger?
2. Is the Carrot and Stick only for Multistage game?
3. Can you please give me example of case using carrot and stick strategy?

I know that it's very basic questions but I am struggling to understand this topic. Thank you!