One, read
the stickies. In this case, specifically:
4. If this is a home server, make sure you know how to forward the port that your server uses from the WAN side of your router to the LAN side of your router. If you have questions on how to do this, post screen shots of your router config page showing the port forwarding setup.
And second, search. The port-forward problem has been answered several times, and a search for 'port forward' or 'forward ports' brings up
this thread.
Have fun.
