Step-1:
On the Webmaster Tools Home page, click the site you want.
Step-2:
Under Crawl, click on Sitemaps.
Step-3:
On your right hand corner, a red button will be available, just click on that button and paste this code.
/atom.xml?redirect=false&start-index=1&max-results=500
Note: If your blog contain more than 500 post, so add this code too.
/atom.xml?redirect=false&start-index=501&max-results=500
