Back in the 90s I wrote my high school's first website. We even got a scan of a picture of the school done in way too high resolution. It was a massive pain to get running, given my buddy and I were in our mid teens and the web was moving fast. Everything was a bunch of different hand crafted pages of tags, served from a machine sitting in the school. But basically we figured out how to do it by reading one or two pages about it.
I left school and eventually did a lot of financial coding, which was mainly backend stuff plus a small amount of desktop GUIs, or very very basic web pages.
Not until a few years ago did I have another look at the web, and it had of course changed enormously. It seems nowadays everything is a tool that compiles into something else. There's a zillion frameworks in js, there's webassembly, there's a bunch of things that you use to build the CSS. The page itself seems to be a load of divs, many tags from the old days are archaic now, only seen on old university sites. Sites themselves are served from a datacenter, and not from one machine. Static content doesn't even need to come from the same place. Security and privacy is a thing. There's no one place to learn the whole thing, which I suppose is expected.