Previewing and replacing 2d sprite animations

Once I got this game set up:

How do I preview sprite animations? Let’s say I want to add more details (frames) to the player idle animation. Is there a way to preview existing animation and to replace the sprites with new ones while preserving existing animation object (speed, transitions) settings?

To be clear, I don’t want to just to edit existing sprite sheet image file, I want to extend it with new frames, ideally just update player animations from my own sprite sheet image file.

Window → Animation → pick an object that has an animator as a component .

You can pick the animation that you want to edit there.