How do you make a light flash when a button is pushed?

You can place a Script like this under the part. Please read the comments though and try to understand how this works by doing more research. This is a website that will only HELP you.

script.Parent.MouseButton1Click:Connect(function()
    for i = 1, 10 do -- second number will indicate how many times you want this to occur so it doesn't have to be 10
    local lights = game.Lighting:GetChildren() -- I'm just assuming that your lights are in Lighting
        if lights.Enabled = false then
            lights.Enabled = true
            wait(0.5) -- however many seconds you want the lights to stay on and it can be a decimal too. If you want flashing lights, then i suggest going for around 0.5
            lights.Enabled = false
        end
    end
end)