How to implement shared components in an After Effects File:
1. Select one or more layers in a composition that should be shared / repeated elsewhere in the After Effects project, and then right click on the layer(s) and select “Pre-compose”. Candidates for this sharing process can vary per implementation, but things like images, logos, transitions, widgets, text blocks, and other design elements can be built once and then referenced anywhere else they are needed using this methodology. Name the new composition with a self descriptive name.
2. Apply any required effects or animations on the layer(s) inside of the precomp. This will help to propagate the changes anywhere the composition is featured, as opposed to to apply effects or animations on the composition itself - which might have to be implemented multiple times.
3. After initial setup, the precomposed composition can be located in the footage panel. Drag the precomp anywhere inside of the project as many times as needed in order to avoid rebuilding the same components repeatedly.
4. By using the precomp throughout your project, any edits inside of the precomp will propagate everywhere the precomp is used, helping to cut down on design iteration cycles. Here are a few examples of universal changes inside of a dynamic precomposed layer:
Dynamic text layers precomped:
Dynamic images or videos precomped: