How would i get player info by the mouse rolling over one?

player.Mouse isn't a thing. If you're referring to the mouse object you made, just use your Mouse variable (canonical names are lowercase though)

Arbitrary objects don't have a GetPlayerFromCharacter method. That's a method of the Players service.

In addition, the Target is the Part, not, the model that the part is in. It can also be nil, so be careful.

Here is one way to put all of that together into a fix:

local target = mouse.Target
if target then
	-- Is hovering over something (not the sky)

	local character = target -- The *part* hovering over
	repeat
		character = character.Parent
	until character:IsA("Model") or character:IsA("Workspace")
	-- To work on Hats, Tool, Gear, we have to
	-- go up an unknown number of levels
	-- Until the workspace, or a model

	local targetPlayer = game.Players:GetPlayerFromCharacter(character)
	if targetPlayer then
		-- `character` is the Character model of player `targetPlayer`
		print(targetPlayer.Name)
	end
end

Additional note:

This will only happen once. -- When the script loads.

For the effect to be useful, this obviously needs to be happening repeatedly; simplest way is to use a while true do wait() loop.