This document provides instructions for using Grunt to compress JavaScript files. It describes installing Node.js and Grunt CLI, creating a project structure and package.json file, installing Grunt plugins, configuring Gruntfile.js to first concatenate JS files and then minify them into a single compressed file, and running Grunt to perform these tasks. The Gruntfile configuration concatenates source files into a combined.js file in the defined order, then uglifies this file to minify it.