Why doesn't this script work properly? {SOLVED}

As you run the script, you'll get the error

input:16: attempt to index global 'Button' (a nil value)

Pretty clearly, that means you haven't defined Button. Which is also clear. Button is only defined in the scope of the function Clicked, we need to define it in the global scope.

You should also tab your code properly.

local Button = script.Parent
function Clicked()
	local Frame = script.Parent.Parent.Parent  
	 local a = script.Parent.Parent.AudioIDInsert.Text 
	local b = script.Parent.Parent.Parent.Parent.MusicForPlayers
	wait(0.1)
	b:Pause()
	b.Volume = 1
	wait(0.1)
	b.SoundId="http://www.roblox.com/asset/?id=" .. a
	wait(0.1)
	b:Play()
	wait(0.1)
	Frame:Destroy()
end
Button.MouseButton1Click:connect(Clicked)