Structure for domains with multiple Node.js apps

I have a couple of domains linked to a web hosting account (shared hosting with A2 Hosting). I want to build a number of different progressive web apps under the domains (several apps under each domain). I want to use Node.js and Express.js but apart from that I want to avoid additional frameworks and just use plain vanilla JS, HTML and CSS (I’m just doing this for fun and as a learning experience). As a beginner I need some advice on how to create the folder/Node.js server structure. I have some stupid questions;

Is it even possible (or advisable…) to have multiple apps (and simultaneously run several Node.js servers) under one domain (I hope so…)

Should I do one Node.js/Express.js installation in the folder of each app? Or should the apps somehow share the same Node.js server??

If I have multiple apps/Node.js servers running do I have to do anything special to make it work? Or is it sufficient that the apps/Node.js have different URI/URL (even though they share the same domain)

Many thanks