Why can't I create a minecraft server on my macbook?

I have been online looking at youtube videos trying to create a multiplayer minecraft serever for 1.7.2. Everytime i did what the person has done on the video i keep getting process complete and logged out. I've tried this process several times for a week and soon gave up. I also looked at different way to do it. I just don't understand, I'm using a macbook retina display. Also this part isn't a question. But if anyone has a serve they wanna share that would be great