Install Bower: http://bower.io npm install -g bower
Update Bower: npm update -g bower
Install all (using project bower.json file):
cd gdg-sacramento-polymer
bower install
Install Polymer: bower install --save Polymer/polymer
Install core-ajax: bower install --save Polymer/core-ajax
Install google-map: bower install --save Polymer/google-map
Install core-elements: bower install --save Polymer/core-elements
Install paper-elements: bower install --save Polymer/paper-elements