what's the practical way to create a sitemap?

If you're on WordPress you probably already have one. Core makes wp-sitemap.xml by itself, and if you run Yoast it's sitemap_index.xml instead. Shopify and most hosted builders generate one too. Then submit it in Search Console under Sitemaps and add a Sitemap: line to your robots.txt. Only thing to watch is that it lists the real indexable pages, not redirects or noindexed stuff.