How to make animation in AE?

Question

Adobe After Effects

There is a figure, as in the first screenshot. How can I make it transform into a position like in the second screenshot? 

I'd like to do it with the pen, just by dragging the slider above, but I don't know how to animate with it.

Answer 1

You need to animate Path. Choose your shape, open the Path parameter inside it, set the key, then change the shape on the next key with the pen. Voila, the animation is ready.