Unless you are modifying or creating your own actions you only need to work with three areas in the Actions panel
Click on the Play selection button at the bottom of the Actions panel to perform the selected action.

You may also choose to use the Button Mode in the Actions Panel. To toggle between the folder view and the button mode click on the menu icon on the upper right of the Actions panel and click on Button Mode. The actions will be displayed as buttons with each set having a unique color. To run an action click on the action name and the action will run. The only problem with Button Mode is that you can’t collapse and expand the various actions sets.
