See the original project on GitHub - https://github.com/Daemonite/material.
SCSS changes as well as JavaScript changes need to be conpiled via Grunt. You first need to install npm via here and make sure that you add it to your system PATH to make everything easier. Once you have npm, you need to install grunt-cli:
npm install -g grunt-cli
You'll also need Sass. To install Sass, you first need to install Ruby via the Ruby Installer (also add that to your system PATH on Windows) and you'll then be able to install Sass via
gem install sass
If you're on Linux, that'll be slightly harder, so see the instructions for installing Sass here.
Once you have Grunt, Sass, and Ruby installed, run the following commands from the root of your project to compile changes:
// To install all additional plugins noted in project.json
npm install
// Wait for the installation of everything to complete before running the next commands.
grunt concat
grunt cssmin
grunt sass
grunt uglify
Note that the commands will run between returns, just like anything else through the command line.