Create a new file named twiggy.libraries.yml within our new theme folder, and add the following configuration information to the file:

global: 
  css: 
    theme: 
      css/styles.css: {} 
  js: 
    js/scripts/js: {} 

Make sure that you also create a CSS folder with an empty styles.css file within it and a JS folder with an empty scripts.js file within it. We will use these two files to manage any visual or interactive theming.