I'm currently learning how to create a site using Wordpress purely with code. I can't seem to find the file where it displays the content of my site (text blocks, image blocks, shortcode, etc.) in pure code form like how html pages have the index.html file, I'm currently using the twenty-nineteen theme. So far I have only been able to make a custom post, I'm trying not to use any plugins while learning. Any help on this would be appreciated.