it's quite long indeed, but I'm sure that you are able to do it, otherwise post it here, and I'll try to help - not being totally skilled in portforwarding as my router can't do it.
The tutorial you posted, is not showing how to the server public, rather how to make it playable on LAN. I want people to be able to connect from their own internet. Maybe you posted the wrong URL? Anyways, not quite what I was looking for.