How would you have a local script and script communicate?

I am making a script for my friend for his racing game. It gives me no error, but It says that there is an unknown global (that I set) is being use. In the Script:

local T = game.Workspace["Add script for laps"].Tester1
local F = game.Workspace["Add script for laps"].Finish
win = nil
over = false
function Create(player)
	local new = Instance.new("BoolValue")
	local new2 = Instance.new("IntValue")
	new.Name = "LapAntiCheat"
	new.Parent = player
	new2.Name = "LapNum"
	new2.Parent = player
end
function Detect1(ob)
	if ob.Parent.Humanoid ~= nil then
		local P = ob.Parent.Name
		if game.Players[P].LapAntiCheat.Value == true then
			game.Players[P].LapNum.Value = game.Players[P].LapNum.Value + 1
			game.Players[P].LapAntiCheat.Value = false
			if game.Players[P].LapNum.Value == 3 then
				over = true
				win = P
				wait(5.1)
				over = false
				win = nil
			end
		end
	end	
end
function Detect2(ob)
	if ob.Parent.Humanoid ~= nil then
		local P = ob.Parent.Name
		game.Players[P].LapAntiCheat.Value = true
	end	
end

game.Players.PlayerAdded:connect(Create)
game.Workspace["Add script for laps"].Finish.Touched:connect(Detect1)
game.Workspace["Add script for laps"].Tester1.Touched:connect(Detect2)

In the local script:

function player()
	if over == true then	
	game.Players.LocalPlayer.PlayerGui.ScreenGui.Winner.Text = "The Winner of this race is" .. win
	game.Players.LocalPlayer.PlayerGui.ScreenGui.Winner.Visible =  false
	wait(5)	
	game.Players.LocalPlayer.Character.Humanoid.Health = 0
	end
end
over.Changed:connect(player)

I will take a big guess and say: Events

Events are used as communication between scripts. Lets say you have a script and a localscript, like you. Here we will make the baseplate a random color when a part is touched!

Script

local event = Instance.new("RemoteEvent") -- Create a new Event
event.Parent = game.Workspace -- Give it a parent
event.Name = "Communication" -- Give it a name
event.OnServerEvent:connect(function() -- Giving the event a function
	print ("Old brickcolor is ".. game.Workspace.Baseplate.BrickColor)
	game.Workspace.Baseplate.BrickColor = BrickColor.Random() -- Running your code
	print ("New brickcolor is ".. game.Workspace.Baseplate.BrickColor)
end)

LocalScript

part = instance.new("Part") -- Creating a part
part.Parent = game.Workspace -- Give it a parent
part.Touched:connect(function(hit) -- If the part is touched:
	game.Workspace.Communicationt:FireServer() -- The event we made will be fired!
end)

Here is the link for the Wiki tutorial: http://wiki.roblox.com/index.php?title=RemoteFunction_and_RemoteEvent_Tutorial I hope this answered your question.