How do Increase a players value in the leaderboard?

make the scripts a normal/ server script put it in serverscript service. if the first script dosen't work try the 2nd one

game.Players.PlayerAdded:Connect(function(plr)
    local level = plr.leaderstats.Level
    while true do
        level.Value = level.Value + 1
        wait(30)
    end
end)

If the first script dosen't work

game.Players.PlayerAdded:Connect(function(plr)
    local level = plr.leaderstats.Level
    while true do
        level = level + 1
        wait(30)
    end
end)

Try adding lines 13 to 16

local datastore = game:GetService("DataStoreService"):GetDataStore("")


game.Players.PlayerAdded:connect(function(player)
    local leaderstats = Instance.new("IntValue")
    leaderstats.Name = "leaderstats"
    leaderstats.Parent = player

    local points = Instance.new("IntValue")
    points.Name = "Level"
    points.Parent = leaderstats

    while true do
    wait(30)
    points.Value = points.Value + 1
    end

    local key = "user-" .. player.userId

    local storeditems = datastore:GetAsync(key)
    if storeditems then
        points.Value = storeditems[1] 

    else
        local items = {points.Value} 
        datastore:SetAsync(key, items)
    end
end)

game.Players.PlayerRemoving:connect(function(player)
    local items = {player.leaderstats.Level.Value} 
    local key = "user-" .. player.userId

    datastore:SetAsync(key, items)
end)