What’s the point?
This is done to google search engine find the other pages on the blog. There are several ways to enter sitemap to Google. The difference is between self hosting blog and not.
For example, a blog with Blogger platform. You can insert sitemap as atom feeds code.
The red writing is amount of article. You can fill as the example so practical for long time, but maybe less effective because the progress will take longer.
Now… if you use self hosting blog… maybe use WordPress platform blog, would be better use sitemap maker plugin. Just search on add new plugins page or use XML-sitemap.
After installing the plugins, configure with filling check box, which option do you think is important. If necessary, find another more complete information about the xml sitemap on the internet.
I hope this may support your blog on google search results.