It's exactly how it works, pages don't just magically appear in Google's index.

You need links to pages either from your own website or backlinks from other websites. Alternatively if the page is in your sitemap then Google will typically pick it up or you can manually submit it for indexing. For important pages you would typically want internal links, backlinks, and have it in your sitemap.

Google indexes links from places other than fiverr, odds are these links are mostly from places like GitHub.