It is different from npm, Here, we use bower package manager to install all Dependencies. so just like it.
$ bower install
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.
This project just a demo for me, if you want to learn polymer, you can use git clone to download. and i have to say that was coooooooool.
guys, have fun.