ELI5 Cloudflare Tunnel

So everyone is talking about cloudflare tunnels and I decided to give it a shot.

However, I find the learning curve quite hard and would really appreciate a short introduction into how they work and how do I set them up…

In my current infrastructure I am running a reverse proxy with SSL and Authentik, but nothing is exposed outside. I access my network via a VPN but would like to try out and consider CF. Might be easier for the family.

How does authentication work? Is it really a secure way to expose internal services?

Thanks!