I am a greenhand for SEO and I haven't learned to use this tool. My friend told me this tool is pretty difficult, is it true. By the way, I have a little knowledge of computer.
Maybe you first read about all the different sitemap tools: http://www.microsystools.com/products/sitemap-generator/help/website-sitemap-kinds-comparison/ And then decide which tool you want to use. And if then asking for help, in future mention what tool you are using for creating sitemaps For e.g. WordPress you may want to use a plugin. For mixed sites a desktop sitemap generator, and for other small and simple sites online sitemappers. There are many solutions out there, some easy to use and some with advanced tools. Use what fits your needs!
It’s not a difficult task at all. You can do it by study some articles about sitemap tools. There are so many tools available for generating sitemap or you can install a plugin for sitemap generator.