what about "<npm start>"

check the working directory is same as the project directory.
you're in the 1 level higher directory of the actual project.

cd my-app

... or you can just re-open vscode in the project folder

its not working

your node_modules and public folder are inside my-app folder, move both of them out or move public folder out and reinstall modules

how to reinstall modules?

its not working

need more info, show the logs

how to do it?

I've few questions, do you know Javascript and react? Based on your questions I am thinking that you are diving straight to Nextjs

i know html css and js and i am just diving into Nextjs

You need to learn React first beforing diving into Next

uh

is react hard or its like js?

React isn't hard but isn't easy either

ok that means i need to learn react first

thanks bro it works

coool!

but, i still suggest that you learn react 😅

Do not delete the original question. Mark the answer instead.