How to generate a sitemap for your blog using blogger

1. Open the Sitemap Generator and type the full address of your blogspot blog (or your self-hosted Blogger blog).
2. Click the Create Sitemap button and this tool will instantly generate the necessary text for your sitemap. Copy the entire generated text to your clipboard (see screenshot below).
3. Next go to your Blogger dashboard and under Settings – > Search Preferences, the enable Custom robots.txt option (available in the Crawling and Indexing section). Paste the clipboard text here and save your changes.

Search engines will automatically discover your XML sitemap files via the robots.txt file and you don’t have to ping them manually.
 
NOTE:  A good PC or Smartphone is advisable to use in this type of situation