Installing Node.js Using JavaScript Code? [closed]

I’ve been programming for decades but am new to JavaScript.

I recently began working on a new project which I want to be able to run
on Linux, Windows and Apple. After some research I decided to use HTML
and JavaScript. I was thinking/hoping I would be able to do the entire
project using only client-side coding, but it doesn’t appear like that’s
going to be the case.

I’ve encountered a point where I need to copy/move files from one location
to another.

What are my options? Node.js?

If Node.js is my only or best option, is it possible to download and
install Node.js using client-side JavaScript code? (Many of the people
who will be using the system will be computer-challenged and/or elderly.
It may be daunting for them if they need to install Node.js themselves.)

I appreciate any help.