I've done this:

local sound = game.Workspace.Ambient1
wait(27)
sound:play()
script.Parent.IntroClip.Frame.Play.MouseButton1Click:connect(function()
sound:stop()
for i=1,100 do
wait(0.02)
script.Parent.IntroClip.Frame.Transparency = script.Parent.IntroClip.Frame.Transparency - 0.01
end
end)

However the sounds played immediately after the game loaded, not waiting the appointed 27 seconds.