Site Map

A sitemap is a way of organizing a website, identifying the URLs and the data under each section. Previously, the sitemaps were primarily geared for the users of the website. However, Google's XML format was designed for the search engines, allowing them to find the data faster and more efficiently.
Side map is look like index. Side map is very helpful go for another page. 

It is great to have a complete and up-to-date sitemap, search engine like it, 
It does not matter site map is created in HTML or special Google sitemap format.
If you don’t want to create HTML sitemap there is so many free tools to create site:
This side help Create side map Build a site map for the search engines and place it in your domain. 

You gives us Fast & Useful us Information on website