Animations are generated based on different visual elements (backgrounds, images, and graphics generated from within the program), which you'll program to perform any moves you want.
Programming these actions is not at all complicated, thanks to the full-featured graphic editor you get in Scratch. It has all the functions you need to create your design and make it perform any way you want. Plus its simplified format greatly reduces the difficulties you'd otherwise normally encounter when it comes to programming movements, playing sounds and modifying how characters behave. Create as many objects as you want, tailor any of the available backgrounds to match and get started making your characters come to life.
Games, animated cartoons, visual caricatures -- sky's the limit when it comes to what you can create thanks to Scratch. Even if you're just starting out on your coding journey, there's no doubt you'll be on your way to making anything you want.