How would I create a cool down time before they can fire again?

I'm trying to make a system which allows a player to shoot a spell, but, I don't want them to be able to continuously use the spell without a cool down. If there is no cool down, the player has the ability to use an auto clicker which spams the spell and creates a load of lag within game, hence why I would like to make one.

However, when I tried creating a cool down, I used a debounce but I kept getting errors and things kept going underlined then other functions of my script wouldn't work.. The script below is the fire script for one of my spells WITHOUT the cool down as mine didn't seem to work.. Please could someone help.

I would like the cool down to be a 0.5 second wait per click..

game.ReplicatedStorage.Powers.OnServerEvent:Connect(function(player, MouseHit, Handle)

if player.Spell.Value == "Water" then

  local S1 = Instance.new("Part",workspace)

  local S1b = Instance.new("BodyVelocity")

  S1.CFrame = Handle.CFrame + Handle.CFrame.lookVector*3

  S1.Anchored = false

  S1.CanCollide = true

  S1.formFactor = "Symmetric"

  S1.Shape = "Ball"

  S1.Size = Vector3.new(1,1,1)

  S1.TopSurface = "Smooth"

  S1.BottomSurface = "Smooth"

  S1.Transparency = 0.5

  S1.Elasticity = 1

  S1.Friction = 0

  S1.BrickColor = BrickColor.new("Bright blue")

  S1b.Velocity = MouseHit.lookVector*100

  S1b.Parent = S1

  game:GetService("Debris"):AddItem(S1, 2)

  local part = S1

  part.Touched:connect(function(hit)

  if hit.Parent then

    local hum = hit.Parent:FindFirstChild("Humanoid")

    if hum then

      if hum.Parent.Name == player.Name then

        wait(0.01)

      else

        hum:TakeDamage(2)

        S1:Destroy()


      end

    end

  end

  end)

end

end)

Thank you.