The all new actions palette provides an easy way to automate certain tasks without learning a scripting language. It does not try to be a scripting language, so it does lack certain capabilities. For full automation, you're better off with something like QuicKeys. Despite its limits, the actions palette does make it much easier to do many repetitive tasks.
All actions are a recording of a sequence of commands.
The three VCR-style buttons on the bottom of the palette reflect this. The triangle plays back an action. The circle records, and the square stops playback and recording. An action is organised hierarchically on the palette, with mac Finder style flip-down triangles. Most commands within an action can be flipped down to view the specifics about that command.