Web Development Essential Concepts

1. Working principle of internet
2. What is Https
3. IP adress
4. World Wide Web
5. URL
6. Hardware
7. Software
8. Web Browsers
9. Web Servers
10. Domains and DNS
11. Html
12. Css (optionally css frameworks)
13. JavaScript (optionally js frontend frameworks and libraries)
14. Links
15. Accessibility
16. Browser Events and APIs
17. NodeJS
18. NPM
19. Error status codes
20. SEO
21. Website Optimization
22. Cloud Hosting
23. Web Security
24. Site Maintenance

Web Dev is a tricky skill to learn and one may never be able to fully learn it. But learning these concepts will at the very least get you started on the right track.