To contribute, you need to do a pull request on the dev branch.
Fork the GitHub project first.
Install node.js, then install npm dependencies:
$ npm install
In order to include elements' doc & demos, you'll need to npm link their working trees:
$ cd core-elements
$ npm link
$ cd bosonic.github.io
$ npm link bosonic-core-elements
Do the same with dnd-elements & data-elements.
You are now ready to go:
$ grunt server
The website is available at http://127.0.0.1:5455.