How does the studio api work? any tutorial are at my game not working.

Hi Community, I am working on a game. I want to make a script that saves the leaderboard when a player left the game. I tried any Youtube tutorial, roblox wiki tutuorial, i tested a lot of scripts from the Toolbox but nothing helps. I tried this: (this is a leader board script)

SummitsData = game:GetService("DataStoreService"):GetDataStore("Summits")
RankData = game:GetService("DataStoreService"):GetDataStore("rank")

game.Players.PlayerAdded:Connect(function(plr)
  local LB = Instance.new("IntValue", plr)

  LB.Name = "leaderstats"

  local r = Instance.new("IntValue", LB)
  r.Name = "Summits"
  r.Value = SummitsData:GetAsync(plr.userId) or 0

  local p = Instance.new("StringValue", LB)
  p.Name = "Rank"
  p.Value = RankData:GetAsync(plr.userId) or "Tourist"

  LB.Parent = plr
  p.Parent = LB
  r.Parent = LB         


end)

and I have this on the game settings: (This are Screenshots) https://www.bilder-upload.eu/bild-c72841-1550513805.png.html

https://www.bilder-upload.eu/bild-8cf6c4-1550513817.png.html

Do you have a solution?

Edit: When I copied the script from my screen I saw the two game files: game.ReplicatedFirstandgame.ReplicatedStorage and game.Networkclient, must I add there something? Are one of this files a "must have" to do this?

Other Info: I saw this youtube tutorials: https://www.youtube.com/watch?v=Wcx7bVBEpCU https://www.youtube.com/watch?v=lS20iM7iRQE https://www.youtube.com/watch?v=c0S1XjD8KzQ https://www.youtube.com/watch?v=YlHNGEvoQNE