Will WordPress installation overwrite files in my main directory?

Hello,

I tried searching but couldn’t quite find the answer. I doubt this will be a problem, but I just want to double check before installing…

I have a site that already has some content on it, including another WordPress blog (www.domain.com/blog). There is also content on there from the original non-Wordpress design I did, but most of this is in folders (e.g. https://www.domain.com/portfolio, https://www.domain.com/contact, etc.)

I want to install WordPress into the “main” directory (is this called the root? not sure), so in other words, when you navigate to my domain, it will go straight to my new WordPress site. This means installing it right into https://www.domain.com. My question is, will this affect the existing WordPress site I have on there, or the existing non-WP folders? I would like to keep those going, and am just afraid the WP installation will overwrite them or something. I know there can’t be two index files in there—that’s fine; I’m mostly concerned about stuff that is in folders.

I hope that was not to confusing. If someone could let me know I would really appreciate it! Thanks!