Please give me sample or links how to create sitemap in Sitefinity.
You can use the Sitemap Generator here (free): http://enterprisefinity.com/products/sitefinity-sitemap-generator/
But you should also be familiar with some of the challenges of creating an all-purpose sitemap generator in Sitefinity. Each piece of content has no set page where it should appear - that depends on the configuration of widgets within your site. So it's difficult to build a solution that understands that (for example) news from the foo department goes here and news from the bar department goes there - Sitefinity just knows that it's all news content.
Take a look here for a better look at the code behind a sitemap generator: http://www.sitefinity.com/blogs/joshmorales/posts/11-12-22/new_sitefinity_4_4_sdk_sample_sitemap_module.aspx