Don’t let lack of knowledge ever be the reason to stop trying something in homelabs! Honestly for a beginner resource ChatGPT is where I’d go for these kinds of questions. It does a great job explaining what all the terms mean and you can drill down into topics as needed such as permissions and different terminal commands you’ll need
Anyways, this link has a decent description of samba:
https://ubuntu.com/tutorials/install-and-configure-samba#1-overview
A Samba file server enables file sharing across different operating systems over a network. It lets you access your desktop files from a laptop and share files with Windows and macOS users.
So as long as a computer is on the network it could access files stored on this hard drive. It is super useful as a first homelab project
Seems they have PWAs, here’s a guide by Mozilla for installing them on Firefox
https://developer.mozilla.org/en-US/docs/Web/Progressive_web_apps/Guides/Installing