Answer:
I hope you're referring to Act V Scene II! Here are the answers:
1) Hamlet switched the note that his father sent to England (the one that ordered them to kill Hamlet) with his own note that informed the reader of the letter to kill whoever delivered it to them. It just so happened that the deliverers of the letter were Rosencrantz and Guildenstern, so Hamlet was responsible for their murder.
2) (I'm not entirely sure about this one) Osric comes to Hamlet and informs him that Laertes is home from college. Osric basically boasts about Laertes' fencing skills for a few paragraphs, and mentions to Hamlet that he should fence with Laertes.
3) At the fencing match, Gertrude drinks the drink that was meant for Hamlet (the one that was poisoned by Claudius) and she collapses and dies.
4) Laertes is stabbed by the poisoned sword and dies.
5) Claudius was also stabbed by the poisoned sword (I think it was in his hand, but I'm not sure). Hamlet also forced him to drink the poisoned water that his mother drank. Claudius dies.
6) Hamlet recommends Young (Prince) Fortinbras to the throne, pretty much because Hamlet relates a little bit to the Prince (mentions how they are in similar situations).
Hope this helps!
