How do I change only one person's stats on leaderboard?

I just started Lua five days ago and I did a little bit of research and I am making a difficulty chart obby. I am making my leaderboard for the obby which tells you which stage you are on and which difficulty you are on. When I tested my leaderboard out in the studio with two players, when one player stepped on the first checkpoint, the leaderboard updated for all players. Is there any way I can fix this? I will show my code down below. Help is very appreciated and thank you in advanced. :)

local players = game:GetService("Players")

players.PlayerAdded:Connect(function(player)
    if player then
        local folder = Instance.new("Folder")
        folder.Name = "leaderstats"
        folder.Parent = player
        local stage = Instance.new("IntValue")
        stage.Name = "Stage"
        stage.Parent = folder
        stage.Value = 0
        local DifficultyChart = Instance.new("StringValue")
        DifficultyChart.Name = "Level"
        DifficultyChart.Parent = folder
        DifficultyChart.Value = "None"
        local checkpoint1 = game.Workspace.Checkpoint1
        checkpoint1.Touched:Connect(function(hit)
            local humanoid = hit.Parent:FindFirstChild("Humanoid")
            if humanoid then
                stage.Value = 1
                DifficultyChart.Value = "Too EZ"

                local checkpoint2 = game.Workspace.Checkpoint2
                checkpoint2.Touched:Connect(function(hit)
                    local humanoid = hit.Parent:FindFirstChild("Humanoid")
                    if humanoid then
                        stage.Value = 2
                    end
                end)
            end
        end)
    end
end)