How i make two lights on?

The issue is that you don't actually have two lights, so how do you expect to turn two of them on?

Try creating a new light instance then copy the code for switching the first light on and edit to the turn the second light on. Remember to make the lights' names different so the code an differentiate between the two.

Although it really looks like a free-modeled script, i will assume good faith and answer anyway.

All you need to do is affect both of the bulbs in the script, like with the one already scripted on.

function LightSwitchwork()
    local state = script.Parent.Parent.Parent.LightState
    local switch = script.Parent
    local lamp = state.Parent.Light.Lamp
    local light = state.Parent.Light.Lamp.SurfaceLight
    local bulb1 = lamp.Parent.Bulbs.bulb1
    local bulb2 = lamp.Parent.Bulbs.bulb2
    if state.Value == false then
        state.Value = true
        lamp.BrickColor = BrickColor.new("Pastel yellow")
        lamp.Transparency = 0.8
        light.Enabled = true
        bulb1.BrickColor = BrickColor.new("Pastel yellow")
        bulb1.Transparency = 0.5 --Here we invoke the bulb itself
        bulb1.SurfaceLight.Enabled = true --Here we invoke the SurfaceLight in the bulb
        bulb2.BrickColor = BrickColor.new("Pastel yellow")
        bulb2.Transparency = 0.5
        bulb2.SurfaceLight.Enabled = true
        switch.CFrame = switch.CFrame*CFrame.fromEulerAnglesXYZ(0,0,0.4)
    else
        state.Value = false
        lamp.BrickColor = BrickColor.new("Medium stone grey")
        lamp.Transparency = 0.2
        light.Enabled = false
        bulb1.BrickColor = BrickColor.new("Medium stone grey")
        bulb1.Transparency = 0.2
        bulb1.SurfaceLight.Enabled = false
        bulb2.BrickColor = BrickColor.new("Medium stone grey")
        bulb2.Transparency = 0.2
        bulb2.SurfaceLight.Enabled = false
    end
end
script.Parent.ClickDetector.MouseClick:connect(LightSwitchwork)