The optional second parameter is Unity layer you want the asset to be associated with. So now Unity has a reference to this sprite sheet: Next we need to define an animation to play. We can do this ...

Sprite Animator is a Unity package that provides a custom animator designed specifically for 2D sprites. It leverages a global frame duration, allowing for full synchrony between animated objects.

Learn how to use sprite sheets, which are images that contain multiple sprites or frames of animation, to optimize your 2D graphics rendering performance and create smooth animations.