Building custom blocks for WordPress. Blocks in WordPress are built in javascript (ES5, or ESNext/JSX then compiled down to js using webpack and bable). If you have used react or vuejs you will be very familiar with this workflow.
Install nodejs
First, you need to have node and npm setup on your system:
Linux: apt install nodejs npm
mac: brew install node
Windows: choco install node
Project init
I always start with git init, and add in a .gitignore: