Make teleportation happen only once when a player joins the game?

My code(not full part) Server: local changeslot1event = Instance.new("RemoteEvent") changeslot1event.Name = "changeslot1event" changeslot1event.Parent = game.ReplicatedStorage local slot1 = Player:WaitForChild("PowerFolder").slot1join.Value

local function slot1up() slot1.Value = slot1.Value + 1 end

slot1up.OnServerEvent(slot1up)

LOCAL: local changeslot1event = game.ReplicatedStorage:WaitForChild("changeslot1event") local join = Player:WaitForChild("PowerFolder").slot1join.Value

button.MouseButton1Click:Connect(function() join = join + 1

if join == 1 then
    TeleportService:Teleport(placeID, Player)

changeslot1event:FireServer() end if join >= 1 then G2.Enabled = true G3.Enabled = false
end

My main problem, is finding a way to get the slot1 join value to increase (slot1 is in data store )