HTML5 question - How many "index.html" can I have on my site?

i’m brasilian, I’m not so good at english.

I am developing a website (I am still a layman, I am learning from it) and on this site I have my main page in case my “index.html” and from what I learned the index.html are the main page of my site.

On my site there will be a menu containing a link to a new “About-Us” page.

My question is if this link I can put a new “index.html” to inform that this index is the main page of “About-Us”.

Or is that invalid and I just leave “about-us.html”.

You can name each HTML file as you wish. If you want each HTML file to have the same name (i.e. index.html) you’ll need to put each in their own folder.