Starting a Github Pages blog

I did jekyll new and then jekyll build, and then jekyll serve and I was able to check my blog on localhost:4000.

I would like to see it through Github Pages, so git push’d my repository’s docs directory. I get 404 on not having an index.html in docs. I have only an index.md. What else than jekyll build should I do to generate the index.html ?

What is the difference between jekyll serve and Github Pages?

there needs to be a _config file in the root in order for GH to know it needs to be built. It sounds like you only pushed part of the root up to GH?