Step 1) Go to the google webmaster tools website

Step 2) Type the url of your website and click "Add Site"



Step 3) Click "Verify your site"



Step 4) Select "Upload an HTML file" from the "Choose verification method..." drop down option box



Step 5) Copy the file name that they say to upload



Step 6) Open notepad or another text editor

Step 7) Save the blank file as the name that you just copied



Step 8) Upload this file to your website. See How to upload a file to google pages



Step 9) Go back to the webmaster tools page and click the "Verify" button



Your Done. You might now want to look at How to add a sitemap to google webmaster tools