Upload a folder to github Git Bash

I borrowed a book called Introduction to GitHub from the library to learn while making it.

I am asking you this question because there is something difficult to understand in this book or just search.

I want to upload a folder like the .github, build, dist, external, src, test folder at https://github.com/jquery/jquery but the folder does not go up

Suppose you have a remote repository portfolio, a local repository portfolio, and a folder BasicFiles in the local repositoryCotton

cd portfolio
git init
git add * //

I thought it would work if I did it like this I searched for add because it doesn't work, and I heard that add can only be a file.

How can I create a folder inside a remote repository?