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.

When you open a template project, After Effects creates a new, untitled project based on the template. Saving changes to this new project does not affect the template project.

A great way to see how advanced users use After Effects is to open one of the template projects included with After Effects, open a composition to activate it, and press U or UU to reveal only the animated or modified layer properties. Viewing the animated and modified properties shows you what changes the designer of the template project made to create the template.

Often, the creator of a template project locks layers that should be left unmodified, and leaves layers that should be modified unlocked. This is a convenient way to prevent accidental or inappropriate modifications.

You can download example projects and template projects from many websites, including the After Effects Exchange on the Adobe website. For more sources of After Effects example projects and template projects, see After Effects community resources.