I need help with a Billboard GUI to use it as a custom name. Any help?

I'm still more of a noob at scripting at the moment, and I need help creating a billboard GUI as a name for my character (Above the head) I'm trying to make it to where it says The Final Boss, and I can't find out how to do just that. Can anyone help me? I've already tried to put portions of other scripts into it, but they don't seem to work. Can anyone help?

Create a new script inside of ServerScriptService then open it and write this

game.Players.PlayerAdded:Connect(function(plr) -- argument "plr" is the player that joined
	plr.CharacterAdded:Connect(function(char) -- argument "char" is the physical character of the plr who joined
		local head = char:findFirstChild("Head") -- finds the player's head
		local bgui = Instance.new("BillboardGui") -- creates a new billboardGUI stored under the name "bgui"
		bgui.Parent = head -- moves newly-created "bgui" to the character's head
		bgui.Size = UDim2.new(5,0,5,0) -- size of GUI (edit if looks incorrect)
		bgui.Adornee = head -- makes the billboardGui show up above the player's head
		bgui.ExtentsOffset = Vector3.new(0,0,1)
		bgui.StudsOffset = Vector3.new(0,3,0) -- offsets it above the head
		bgui.AlwaysOnTop = true -- visible above any part
		local text = Instance.new("TextLabel") -- creates new textlabel
		text.Parent = bgui -- moves newly-created textlabel to the billboardgui
		text.Text = "The Final Boss" -- self-explanatory
		text.BackgroundTransparency = 1 -- makes background of textlabel invisible
		text.Font = Enum.Font.SourceSans -- sets font of the text		
	end)
end)

accept answer if this helped.