Install the extension from the Chrome Web Store:

https://chrome.google.com/webstore/detail/pmbfkcgplcmlmoccjbcgmopkbefndhpd

If you want to try the code from source, download a zip, extract it, then in chrome:

1. Go to the url: chrome://extensions
2. Turn on "Developer mode" by clicking the link in the upper-right
3. Click "Load unpacked extension..."
4. Select the directory you just extracted above

Feel free to add features and submit pull requests.