error attempt to index nil with 'CharacterAdded'? I need help

`iv been working on my Checkpoint for month and I cant find the problems so I came here for answers.

game.Players.PlayerAdded:Connect(function(player)
	
	local stats = Instance.new("IntValue", player)
	stats.Name = "leaderstats"
	
	local Stage = Instance.new("IntValue", stats)
	Stage.Name = "Stage"
	Stage.Value = 1
end)

player.CharacterAdded:Connect(function(Character)
	repeat wait()until player.Character ~=nil
	local hum = Character:WaitForChild("Humanoid")
	wait()
	Character:MoveTo (Checkpoints[Stage.Value].Position)
	
	
end)

Oh and the script is in the ServerScriptService if that helps.

BTW it says unknown global player, checkpoint, and Stage if that also help.