Im trying to turn the player's arms towards the player's mouse, but how?

Hey Coders! Im trying to turn the player's arms towards the player's mouse. Im talking about a server script. But I have trouble with it for a long time, so please help .. basically as here: how-can-i-make-fake-arms-that-follow-the-mouse-like-in-fps but in R15

Yes, I googled it before i asked..