You need to understand how animations are organized on your computer, and how this relates to what you see in the Animation Library workshop in Composer.
Animations are organized in groups. Each group corresponds to a sub-folder in the AnimationLibrary folder. There are two groups for pre-defined animations, Highlight and Motion. Consequently, your AnimationLibrary folder contains two sub-folders, Highlight and Motion. You can add sub-folders as required to create custom animation groups.
Each group/sub-folder contains a set of XML files. Each XML file corresponds to an animation. For example, the Highlight animation folder contains a file called Enhance.xml. This file corresponds to the Enhance pre-defined animation, available in the Highlight group of the Animation Library workshop.
Animations themselves are made up of a number of motions. For example, the Enhance animation contains the following motions: Flash and Scale. In the Animation Library workshop, the motions available for the selected animation are listed, and you can customize the properties of each motion.