Clone this repository with git and check out the branch that you are interested in (or choose the branch first and then download the archive, but learning how to use git really makes sense).
Change to the repository directory and run
npm installto install required modules. Afterwards, you can build the project using
npm run buildor, if you want to let everything be built continuously while you are making changes to the code, run
npm run watchBefore putting the code in production, you should always run npm run build.
The build process will transpile ES6 to earlier versions in order to improve compatibility to older browsers. If you want to use particular functions that some browsers don't support, you'll have to add a polyfill.
The build process will also move the source files into one distribution file and minify the code.