What does one need to know to create a website? What are the steps?

I have a lot of questions and I don't truly know where to ask them so here we are. The assumption is that the website that a user wants to create is a newspaper website (example theoutline.com, wired.com). (Optional) How would it change if it's a social media website like facebook.com?

Along the process of web development: 1. (What is the starting point?) Do web developers start from scratch usually? Would a good web developer use platforms such as wordpress? webflow? wix? etc.

2. (What knowledge do you need?) What technologies you need to know to create a website. What would a user need to know except HTML, CSS? Is javascript the only option or are there alternatives to it? Is Python an alternative to javascript?

3. (Uploading and page maintenance?) What happens after a user has developed the code for the website and it is all stored in folders? Does one just upload everything copy-paste style? How do you go about adding new content? Let's say it's a newspaper publication. How do you upload a new article in that scenario? Would you have to change the HTML, CSS every time to include the new article?

Please be as detailed as you can be and as much as time allows. I'm sure a lot of other people have the same questions and clear answers would be very helpful. Thank you!