The index.html file is using the home layout, which means that it will use the content of that file (_layouts/home.html) to display your content.
So if you want to display your own content, you would need to change the layout to page or default if you want more control.
You might want to remove the breadcrumb or modify its label as well.
You’ll get something like:
index.html
---
layout: page
title: Your custom title
---
Content of this page using <abbr title="Hypertext Markup Language">HTML</abbr>.
You could also create your custom layout, or modify home for your needs.
You can read more about layouts in this page:
I would recommend to read the whole step by step guide 