First, install bower dependencies bower install and make sure you have the Polymer CLI installed. Then run polymer serve to serve your application locally.
$ polymer serve
$ polymer build
This will create a build/ folder with bundled/ and unbundled/ sub-folders
containing a bundled (Vulcanized) and unbundled builds, both run through HTML,
CSS, and JS optimizers.
You can serve the built versions by giving polymer serve a folder to serve
from:
$ polymer serve build/bundled