Amusingly you can't launch it from the creative cloud launcher, but it should be available from your Windows start menu. Restart creative cloud, you'll find Extendscript Toolkit CC. Go to creative cloud, prefs, turn on 'show older apps'. Turns out its hidden, this page gave clues to where it is:
Several tutorial sites mention a scripting interface, but I couldn't find it. Hit the windows key and R at the same time, type 10.2 JSX isn't very strict about syntax.
