That's something I don't know, I don't use Airport Extreme but this is a good site: http://portforward.com/english/routers/port_forwarding/Apple/AirPortExtreme/Minecraft_Server.htm
Google how to get to "Port Mapping"... Come on man do your own research. Once you get to port mapping you just click the + sign and tadaaa..
If your not even going to bother trying to use the internet, why should we give up our time to tell you a thing ? Stop being lazy and actually try to find the information yourself. You have made 3 threads and you've been given information on how to port forward. If you aren't going to be bothered to read these responses, then don't expect people to bother giving you support.
I am I really am, I just don't understand how to do a bunch of stuff in the tutorials/guides, and don't tell me to not try running a server because I'm not giving up after 2 days...