In this tutorial, Rutger McKenna walks you through creating a basic scene in Phaser 3, creating shapes, and loading and displaying images in your scene. Rutger walks through the basic boilerplate that is needed to create your Phaser game.
From the article: "Mainly when you start looking at Phaser from a JavaScript perspective, one can see some similarities to other frameworks that JS is used in; namely React! If you have a background in React than you’ll see some common similarities between the programs. The good news is, Phaser is much more simplistic than React. Really what is similar is the idea of holding state and passing around attributes to different objects."