Demo
Step 1
Download the javascript files, or install via npm
Step 2
Enqueue the JS files in your child theme’s functions.php
Step 3
Create the HTML structure in a the file names parallax.php
Your Child Theme/templates/home/parallax.php
Step 4
Add some line of SCSS
Step 5
Create the shortcode for the above created parallax.php file
Step 6
Put the shortcode [parallax] wherever You want to be shown the parallax background.