Hey, When i first created website for my client. It required SEO so, I started doing that and came across robots.txt and sitemap for better SEO. To accomplish my task I searched for some good references. and i am glad i found some. I think it will be better if I shared it.

XML Sitemap and Robots.TXT Guide for SEO Beginners from Aditya Todawal

--Official resource --

On-line sitemap generators.

If you find more relative resources, please share.