How would I weld the hat into the players head?

I was told I needed to weld the hat into the players head, although with that I have no actual idea how to weld things (I script GUIs and stuff but not items) How would I do this?

This is my script

local Player = game.Players.LocalPlayer

local HatsAvailable = {}

local Count = 0

local LeftButton = script.Parent.LeftHat

local RightButton = script.Parent.RightHat

for i,v in pairs(game.ReplicatedStorage.ClothingLow.HatsLow:GetChildren()) do
	table.insert(HatsAvailable,v)
end

function RemoveCurrentHats()
	for i,v in pairs(Player.Character:GetChildren()) do
		if v.ClassName == "Accessory" then
			v:Destroy()
			print("RIP HAT")
		end
	end
end


function Update()
	script.Parent.Buying.Value = true
	RemoveCurrentHats()
	script.Parent.ItemName.Text = HatsAvailable[Count].Name
	script.Parent.Price.Text = "$"..HatsAvailable[Count].Price.Value
	local HatTheyBoughtClone = HatsAvailable[Count]:Clone()
	HatTheyBoughtClone.Handle.HatAttachment.Position = Player.Character.Head.Position
	HatTheyBoughtClone.AttachmentPos = Player.Character.Head.Position
	HatTheyBoughtClone.AttachmentPoint = Player.Character.Head.CFrame
	Player.Character.Humanoid:AddAccessory(HatTheyBoughtClone)
end

script.Parent.LeftHat.MouseButton1Click:Connect(function()
	if Count >1 then
		Count = Count - 1
		Update()
	end
end)

script.Parent.RightHat.MouseButton1Click:Connect(function()
	if Count >= #HatsAvailable then
	else
		Count = Count + 1
		Update()
	end
end)

script.Parent.Parent.Decline.MouseButton1Click:Connect(function()
	script.Parent.Parent.Parent:Destroy()
end)

Like I said no actual idea how to weld anything