How do you force First Person Mode?

I am trying to force first Person mode for a game of mine and I dont even know where to start, please I need some help.

script.Parent.Parent.CameraMode = Enum.CameraMode.LockFirstPerson--- put in starter GUI!

or:

--First Person Camera
--by Ozzypig, June 2012.

function onPlayerSpawned(player, character)
	player.CameraMode = "LockFirstPerson"
end

function onPlayerChatted(player, message, recipient)
	if player.userId == game.CreatorId and game.CreatorType == Enum.CreatorType.User then
		if message == "/thirdperson" then
			player.CameraMode = "Classic"
		elseif message == "/firstperson" then
			player.CameraMode = "LockFirstPerson"
		end
	end
end

function onPlayerEntered(player)
	player.CharacterAdded:connect(function (char) onPlayerSpawned(player, char) end)
	player.Chatted:connect(function (msg, rec) onPlayerChatted(player, msg, rec) end)

	player.CameraMode = "LockFirstPerson"
end

game.Players.PlayerAdded:connect(onPlayerEntered)

NOT MADE BY ME!!!!!!!!