1. Create animation in After Effects (with a transparent background.)
2. Export the comp as a PNG Sequence (or animated GIF)
3. Compress the PNG sequence into a ZIP file
4. Export the audio (optional)
5.Transfer the files to the mobile device.
6. Create a new scene in Adobe Aero
7. Import the PNG sequence ZIP file
8. Add a TAP behavior to the PNG sequence
9. Add a PLAY IMAGES actions to the behavior
10. Add a PLAY AUDIO to the behavior and select the audio file.
11. Press Preview to see the animation.
In order to avoid playback lag, optimize your files as much as possible. Keep the dimensions of your animation as small as possible (while maintaining fidelity) and keep the FPS as low as possible.