Here are some resources to help you get started,
Codecademy - Provides some of the best courses to get started with web design for complete beginners: Learn
- W3schools - W3Schools Online Web Tutorials
- Freecodecamp - Learn to code and help nonprofits
- TheOdinProject - Learn Web Development for Free
Further learning tips:
- Don't just learn and forget. Do while you learn. Have side projects, look at your favorite websites and try to replicate their design.
- Practice practice and practice some more, that is the only way to get better at it, can't stress this enough.
- Don't stop after HTML/CSS/JS, learn frameworks, there are many. Start with Bootstrap - Bootstrap · The world's most popular mobile-first and responsive front-end framework.