Menu Bar: Home to some menus, some file information, and the Preview and Publish Buttons.
Common Bar: Tools to configure, position, align, and arrange your objects.
Project Panel: Blueprint for your applet's structure, navigation, and content.
Design Panel: Launchpad for lots of awesome media and interactivity, like images, animation, video, buttons, and other great building blocks for a cool user experience. Also provides a browser of reusable assets which can be uploaded in a batch or individually.
Properties Panel: Control Panel for any selected object, exposing all the configurable knobs and dials.
Page Space: "On-screen" space for you to place objects.
Scratch Space: "Off-screen" space for you to place objects.