Okay, so, I thought about making an arm that points to the direction my mouse is pointing but I can't figure out how in the world I could do that... I just don't understand how to do it. I've tried several times but I can't get it to work. I've also tried doing it with the cameras CFrame property or something but I get no result, in fact, sometimes my screen goes white and my character dies... Please let me understand how this scripts that make an object aim to the place that the mouse is pointing. Help is always appreciated, thanks!
arm.CFrame=CFrame.new(arm.Position,mouse.Hit.p)
This will make the front of the arm face towards the position of the mouse. You will probably have to edit this, as I have not tested it.