The pad stadium lights are automatic, controlled by the sun angle. Everything else is controlled through the LC39 Structures Control dialog window which can be accessed by pressing Ctrl-Spacebar with the pad vessel as the focus (it should be named either LC39A or LC39B). But it's really just for testing purposes right now, as SSU itself can only handle the countdown from T-9 minutes and onward(Terminal Countdown). There's no support whatsoever for earlier countdown activities due to the limited system implementation(For example, no Electrical Power System or any prelaunch software).
