If you are confused about the last part on how to open ports. You have to download the latest java. To make a server you need to open or enable ports. You have to do that on your firewall and ,if you have a router, on your routers sytem. Everything is explained on Portforward.com
Links:
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HOT! A Java JDK Fix to make it work! http://ozuungo.notlong.com
Latest Minecraft Alpha 1.2.2 version [you can play online with your friends with this one]: http://bit.ly/downloadMC (downloads: 72)
Hey0 Server Mod[Latest for free] (That in the video is old lol.): http://bit.ly/MCmod125 (downloads: 59)