How would I add sound to this?

When ever you take damage, such as if it's more than 50, it'll play a sound, and if it's below 50, it'll play a sound and if it's below 20, it plays a sound?

local self = script.Parent
local Humanoid = self:WaitForChild("Humanoid")
local Regen = false
Humanoid.HealthChanged:connect(function()
    if (not Regen and Humanoid.Health > 0) then
        Regen = false
        while (Humanoid.MaxHealth > Humanoid.Health) do
            local NewHealth = Humanoid.Health + (Humanoid.Health/Humanoid.MaxHealth) + 0.5
            Humanoid.Health = NewHealth
            wait(Humanoid.Health/Humanoid.MaxHealth * 0.00001)
        end
        if (Humanoid.MaxHealth < Humanoid.Health) then
            Humanoid.Health = Humanoid.MaxHealth
        end
        Regen = false
    end
end)