Browse to www.google.com/webmasters/ and click the “Sign in” link.
(Note: There is also a video here that provides a worthwhile overview. )
Once in, you will need to click the “Add a Site” box,there is again a verification process to ensure you are the owner of the site. This can be done through a few different methods, any of which only take only a few moments. Once your website is setup and authenticated in Webmaster tools. It will be listed and any critical issues will be identified so you can address them and improve your site search ability.

