were would i put a poison script in, in the case of a gun?

i tried putting it in the local script for starter pack but that didnt work, i want it so when you get shot by the gun then you lose hp over time. here is the script i put in; local Player = game.Players.LocalPlayer local Char = Player.Character repeat wait(10) until Char local Hum = Char.Humanoid local Damage = 5 --How much damage it does while wait(10) do --Loop wait() --Wait how much you want until the poison hurts again Hum.Health = Hum.Health - Damage end