To start learning how to make your own visualizers or video games, you need to first learn how to use Processing. 

Since it was originally developed, Processing has evolved and is now available right in the web browser.  At Piper we use the version of Processing for the browser called p5.js

From the p5.js website:

"p5.js is a JavaScript library for creative coding, with a focus on making coding accessible and inclusive for artists, designers, educators, beginners, and anyone else! p5.js is free and open-source because we believe software, and the tools to learn it, should be accessible to everyone."

• Visit this website to get started: https://p5js.org/get-started/