you are thinking what the sitemap is,how it will help you. To index your blog to Google search engine , you are to submit sitemap. The Google bot will crawl and index pages of your blog, if any problem occurs it will show status error.It also help you know what people searched in search engine to find your blog.To make your blog popular it is necessary to add sitemaps in search engines.
Step 1: Visit Google Webmaster Tools and sign in your google account.
Step 2:Add your site here.Don't use http:// before your blog or
Step 3: Verify your site.There are two steps to verify it.
Choose Add a meta tag
(from verification method drop down menu).
Step 4:Now you will see a meta tag just like this image.
Copy this meta tag.
Step 5: Paste this meta tag just after (head) tag.Just like
this image.If you don't know how to edit HTML in blog, visit
Edit HTML In Blog.
Step 6: Click on verify button . You see this button on Step 4.The site or blog will be verified within few minutes.
Step 7: This is last step.Now
submit sitemaps as image at right.You can add more than one.Some options:
You can check it after few hours.You will see details(errors or index pages or url etc) about your blog or site.