My kids love Minecraft. They often run a curseforge mod (create?) and then open a port so they can play together inside the home LAN.

But, I don't really understand how this works, and I would love to host it in a way that their cousins in another state could join. Do you know how I research this?

I get a bit confused between the curseforge mods, the java edition. Should I start by downloading a JAR of the server and host it on a cloud server somewhere, and then firewall it off to only permit my NAT IP and the cousin's NAT IPs? At some point maybe I can run it all within a wireguard/tailscale network.

How do I get started in my reading? I'm worried I'll get overwhelmed by reading /r/MinecraftBuddies, but perhaps that is a better place to ask?

This may be enough to get the ball rolling:

https://blogs.oracle.com/developers/post/how-to-set-up-and-r...

First off, it's generally a good idea not to port-forward your own home router outside of defaults (Even if it's just 25565; I created a nightmare scenario for the ISP guy back at my parent's house when I was around 13 doing this).

There's tons of options to host servers in the cloud with near absolute control. I used to use a SaaS company called Minehut (https://app.minehut.com/) before I got into cloud computing and using AWS EC2 (https://aws.amazon.com/blogs/gametech/setting-up-a-minecraft... - like $8/month).

If they're interested in learning the nitty-gritty on cloud computing and hosting (they probably do if they're already learning Curseforge), then get them into the AWS method. If you want something one-and-done, opt for Minehut.