Ever wondered how you can create a transition for three scenes in Ae and have them all take up a third of the screen? It’s actually pretty easy, and it can be adapted to work with projects that you already have. Evan Abrams has a great overview of how to create a 3-panel manage, or an animated triptych, using mattes and a few keyframes.
Easily make a 3-panel montage in your motion graphics pieces
The final result looks a lot more complex than it actually is. Evan is a master of process and clever reuse of elements in After Effects so that animations are built easily and successively.
There is a neat trick to have the subject of each panel of the triptych respond to the motivating animation in the scene.
Evan provides the After Effects file for you to work along with, here.