How to port forward a Minecraft server on Airport Extreme?

Please don't ignore this! The last questions I asked were ignored:'C
I have a Airport Extreme Router (Version 7.7.3) and Minecraft 1.7.9. I have made a Custom CraftBukkit server recently using my own computer as the host. I tried to port forward by logging into the Router on a *MAC* (NO WINDOWS INSTRUCTIONS Please! I BEG YOU!) using Airport Utility, going into network, clicking the plus sign below port settings, and typing in the description Minecraft_Server, and putting 25565 into everything but Private IP Address, in which I put the IP address shown in System Preferences/Network. I changed the IP in the server.properties file to match the value entered into Private IP Address. Did I do something wrong? Also, if there's a solution that involves spending money for something, I can't do that. I have no money to spend right now (I spent it all). I CAN access the server on my computer by typing into the Direct Connect bar in minecraft "localhost". Also, when I have tried to connect on a separate account on a separate computer I used these IPs:
-my private IP
-my private IP with:25565 at the end