In your question concerning Shakespeare's Hamlet, you don't name the scene you're asking about, but you do mention the quarrel with Norway. I'll assume, then, that you're referring to Act 1.2.
In this scene, Claudius reveals much exposition in his opening speech. He reveals that his brother, the king, has recently died, that Claudius has married his dead brother's wife, and that young Fortinbras from Norway is after land that his father lost to the former Danish king, Claudius's brother.
Concerning Norway, the former King Hamlet defeated the former King Norway and won a bit of land from him. Norway was killed in the battle. Norway's brother also took over the throne of Norway, as Claudius has taken the throne of Denmark. Norway's son, Fortinbras, now wants the lost land back.
To prevent this conflict, Claudius sends messengers to the new king of Norway, informing him of Fortinbras's behavior. He assumes the new king will stop Fortinbras.