An After Effects project is a single file that stores compositions and references to all of the footage items that you use in that project. Compositions are collections of layers. Many layers use footage items as a source, though some layers—such as shape layers and text layers—contain graphics that you create within After Effects. A project file has the filename extension .aep. The name of the current project appears at the top of the application window.

A template project is a file with the filename extension .aet. You can use the many template projects included with After Effects—including DVD menu templates—as the basis for your own projects, and you can create new templates based on your projects.

A great way to see how advanced users use After Effects is to open one of the template projects included with After Effects, select all of its layers, and press U or UU to reveal only the animated or modified properties. This shows you what changes the designer of the template project made to create the template. You may need to unlock some layers to select them.