Welcome! You found a CS First Starter Project for the Music & Sound theme. Watch this video at CS First to learn how to build it: https://csfirst.withgoogle.com/c/cs-first/en/music-and-sound/dance-party/remix-the-dance-party-starter-project.html If you're a teacher: Lesson plans are also available on the CS First site. If you decide to sign up for a CS First account, you'll be able to track your students' progress, order physical materials (kits), and access your students' projects in Scratch.
I used mouse pointer position in my code to move the cat. Feel free to move your mouse pointer anywhere on the backdrop while the music is playing to make the cat move there.