Where do I find the index.html file?

Where does one find the index.html file?

You are working in it:

see top? it says index.html, all the code you write (at this point of the course) is in index.html

Yes but, If I wanted to start from scratch. What do I download or install

In you local document folder, create a site root folder with your project name, then navigate inside it. Create a new text file and save it as index.html. Nothing to install. You have a text editor and a browser; that is all you need.

Inside that folder create three moreā€¦

css
js
images

Store your style sheets in the CSS folder, your scripts in the JS folder, and all your images in the IMAGES folder, then compose your HTML page with links to the other resources.