How to add autosave/autoload to this script?

Lines 1-12: New IntValues Lines 14-17: A level for each 100 EXP

game.Players.PlayerAdded:connect(function(plr)
 local stats = Instance.new("IntValue", plr)
 stats.Name = "leaderstats"
 local EXP = Instance.new("IntValue", stats)
 EXP.Name = "EXP"
 EXP.Value = 0
 local level = Instance.new("IntValue", stats)
 level.Name = "Level"
 level.Value = 0
 local Souls = Instance.new("IntValue", stats)
 Souls.Name = "Souls"
 Souls.Value = 0

 EXP.Changed:connect(function()
  if EXP.Value == 100 then
  EXP.Value = 0
  level.Value = level.Value + 1
  end
  end)
end)