How to acheive authorization ? How to prevent a user from directly accessing my html pages by writing URL?

I'm working on a node-red project with uibuilder node. It's basically [html, css, js(with vue)] pages.

I want to make the login authorization part where each user opens the allowed pages only.

How can I acheive that? by tokens? by permitting direct access to pages using URL?

P.S. I'm new to this part of web and I tried searching but couldn't find what I need.