I want to make a blogger theme development

Question

I have learn HTML5 and css , but theme settings is not working properly and functions

Answer 1

Do you mean How to create a theme for the Blogger platform?
If so visit the blogger Help Center.
https://support.google.com/blogger/answer/1227173
There is also a blogger community forum.
https://support.google.com/blogger/community
If no, please provide your code or elaborate so that we can better understand the issue.

Answer 2

You might be interested in the sololearn Web Development Fundamentals course.
https://www.sololearn.com/Course/web-dev-basics/?ref=app
If you need help with vide, please link your code.