First, log in your Google webmaster tools account and click the "Add a site" button. The small form field will appear. Enter the URL of your website to this field and click "Continue" button.
In the next step you will need to prove that you have the right to access the data which Google gathers about your domain. There are two ways how to confirm that you are the website owner – meta tag verification or verification using HTML file.
1. If you choose the first way, you will need to paste meta tag google-site-verification into your home page. This tag looks like this: meta name = "google-site-verification" content = "some-numbers-and-letters". This piece of HTML code must be added between the and head> tags in order to work properly.
2. If you choose the second way, you will be asked to download a HTML file and upload it to your domain. Then you will need to visit yourdomain.tld / downloaded-file.html in your browser.
No matter which of these ways you choose, when done you need either click the "verify" button to complete the process or "verify later" button for later verification. As soon as you finish this verification process, you will get immediate access to the Google webmaster tools and take advantage of all its features.