First, make sure you have the Polymer CLI installed. Then run polymer serve to serve your application locally.

$ polymer serve

$ polymer build

This will create builds of your application in the build/ directory, optimized to be served in production. You can then serve the built versions by giving polymer serve a folder to serve from:

$ polymer serve build/default

$ polymer test

Your application is already set up to be tested via web-component-tester. Run polymer test to run your application's test suite locally.