How can I share ports with an Apple router?

I would like to share the 25565 port to make a minecraft server accessible to friends. Now the problem is that you can't enter the default gateway address with Apple routers as with all other routers to configure it, but with a software. Now I do not understand what I'm doing wrong:

You now enter the local IP of your server under the private IP address, as well as again the same port under private TCP port.

You have to tell the program which public port to forward to which private port.

And since there are (usually) several computers in a network that can use the same port, you still need to enter the private IP address of your compter.

That You contribute with private port still the same as with public ones (25565) and with IP address you have to just https://www.tippscout.de/mac-ip-adresse.html

I assume I have to give a static IP to my PC serving as a server

That would be ideal.

How does that work at the airport? I'm really not sure

I do not know about Applehardware. You may have to buy an app for this.

Too bad, thanks anyway