The timeline is where your animation comes to life. It’s the control center for every layer and keyframe you create.
Steps to use the timeline
At the bottom of After Effects, you’ll see the timeline. Each layer shows up as a horizontal bar — that bar represents how long the layer lasts in your composition.

Move the playhead (the blue vertical line) left or right to scrub through your project and preview what’s happening. Drag the ends of a layer bar to trim it shorter or extend it longer.

To see a layer’s transform properties (Position, Scale, Rotation, Opacity), just hit P, S, R, or T on your keyboard — each letter reveals one property.

Click the stopwatch icon next to any property to create a keyframe.

Move the playhead, change the value, and After Effects automatically creates another keyframe. The animation happens between those two points.

One more thing
Press U on your keyboard to reveal all the keyframes on a selected layer — super handy when you’re working on complex animations and need to see everything at once.
Related how-tos
How to zoom and navigate the timeline in After Effects
How to create precomps in After Effects
How to use easing for smooth animation in After Effects
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