How do I make the ability do dmg per second?

I need to make it to where the ability does 3 dmg per second when a player a touching it

--Server Script--
local tween = game:GetService("TweenService")
local casting = false

script.Parent.RemoteEvent.OnServerEvent:Connect(function(player)
    if casting == true then return end
    casting = true

    local iceSpikes = game.ReplicatedStorage.LightCage:Clone()
    local dmg = 3
    --Pre position
    iceSpikes:SetPrimaryPartCFrame(player.Character.HumanoidRootPart.CFrame)
    iceSpikes.Parent = workspace
    local endPositions = {Position = {}, Orientation = {}}
    for i,v in pairs(iceSpikes.Spikes:GetChildren()) do
        endPositions["Position"][i] = v.Position
        endPositions["Orientation"][i] = v.Orientation
        v.CFrame = CFrame.new(iceSpikes.Center.Position)
    end

    --Activate
    wait(0)
    local Sound = script.Parent.Lightning
    Sound:Play()
    for i,v in pairs(iceSpikes.Spikes:GetChildren()) do
        v.Orientation = endPositions["Orientation"][i]
        tween:Create(v, TweenInfo.new(0), {Position = endPositions["Position"][i]}):Play()
    end

    --Attack
    for i,v in pairs(iceSpikes.Spikes:GetChildren()) do
        v.Touched:Connect(function(hit)
            if hit.Parent:FindFirstChild("Humanoid") and not hit:IsDescendantOf(player.Character) then --Check if its a player
                local enemyHumanoid = hit.Parent:FindFirstChild("Humanoid")
                enemyHumanoid:TakeDamage(dmg)
            end
        end)
    end

    --Remove
    wait(5)
    Sound:Stop()
    iceSpikes:Destroy()
    casting = false
    wait(2)
    if iceSpikes.Parent == workspace then
        iceSpikes:Destroy()
    end
end)