Hi, sitemaps are easy to make with SEO plugin. I have yoast that is one of the best
SEO plugins and it does automatically and sends sitemaps to search engines without any need for us to do it ourselves. But you can do it manually too, and submit it to Google search console (after submitting your site to Google index and it approves your content). A sitemap should look like this: www.example.com/post-sitemap.xml
But you can send also sitemaps of images, tags, and so on so I strongly advice you to get a SEO plugin and let it do it for you automatically. But before that, you must index your site on Google. go to your browser and write something like this: site Google index. And follow the instructions given by Google.