This guide has now moved to here https://github.com/OnniSaarni/SPT-Fika-Docker-Guide
This gist can still be used for discussion if you'd like.
Feel free to make an issue or a pull request if you'd like to contribute by expanding some sections or just otherwise contributing something to the guide.
Scripts and automated tools are welcome too if you wish to have them in the repo.
@B0d4 this is not a server issue but you'll have to port forward 25565 udp or use a VPN with your friends. You'll also have to add the windows firewall rules manually or with the tool in the Fika discord #faq. For further support please go to the #questions or #support channels.