How do I make these lights change using a folder?

I'm trying to make a light switch that can enable or disable lights in a folder when I try to, the output says it can't find anything in the folder, the part doesn't show up in the suggestions box either. This is the script I'm using, (not including the light switch) it only enables and disables one light and works, but it would get crowded quickly and would look bad if I did this for everything.

if open == false then
    workspace.Light.SurfaceLight.Enabled = true
    workspace.Light.Material = Enum.Material.Neon
    workspace.Light.BrickColor = BrickColor.new("Light stone grey")

    script.Parent.Parent.Parent.LightsA.Green.Transparency = 0
    script.Parent.Parent.Parent.LightsA.Green.Material = Enum.Material.Neon
    script.Parent.Parent.Parent.LightsA.Red.Transparency = .3
    script.Parent.Parent.Parent.LightsA.Red.Material = Enum.Material.Glass
else
    workspace.Light.SurfaceLight.Enabled = false
    workspace.Light.Material = Enum.Material.Glass
    workspace.Light.BrickColor =  BrickColor.new("Black")

    script.Parent.Parent.Parent.LightsA.Green.Transparency = .3
    script.Parent.Parent.Parent.LightsA.Green.Material = Enum.Material.Glass
    script.Parent.Parent.Parent.LightsA.Red.Transparency = 0
    script.Parent.Parent.Parent.LightsA.Red.Material = Enum.Material.Neon
end
       end
end)

Thanks in advance if you're able to help me.