How can I make a hat giver surface gui?

I'm trying to make a Surface GUI button which makes the player wear a hat when it is clicked. Here's what I've tried so far -

script.Parent.MouseButton1Click:connect(function()

debounce = true
function onClicked(plr)
if debounce == true then
debounce = false

local h = Instance.new("Hat")
        local p = Instance.new("Part")
        h.Name = "Hat"
        p.Parent = h
        p.Position = plr.Character:findFirstChild("Head").Position
        p.Name = "Handle" 
        p.formFactor = 0
        p.Size = Vector3.new(2, 1, 1)
        p.BottomSurface = 0 
        p.TopSurface = 0 
        p.Locked = true 
        script.Parent.Mesh:clone().Parent = p
        h.Parent = plr.Character
        h.AttachmentPos = Vector3.new(0,.8, 0)
        wait(5)
        debounce = true

end
end
end)


script.Parent.ClickEvent.OnServerEvent:connect(onClicked)

Anyone know how to fix this?