The free app Learn After Effects: 2021 provides you with an in-depth, easy-to-understand course on the fundamentals of After Effects and video editing in general.

The lessons are divided into sections that cover a wide range of topics, such as video editing with After Effects, color, masking, effects, and more. 

Each section includes several lessons, with a corresponding amount of video and a set of exercises to help you master the skills that are being taught. This way, you can go at your own pace and learn as much as you want.

To help you get started, you can follow along with the text and watch the videos from the app. You can also access a free, downloadable version of the app if you're on a mobile device.