You need to set the options in your registrar (the company you bought your domain through) to pint hostgator DNS (that you got from hostgator email) to point to hostgator. Netherworld Hostgator sent you two DNS in the welcome email (if you don't have the email then go into your cpanel). From here you go into your Registrar settings and somewhere there is a field that you put these two hostgator DNS into. And Save. After that, you should be live.
Note Marcus has lots of videos on how to do this. Almost everything on Webinar or videos that he talks about finding a niche and using his trigger word list, he covers how to get you site to go live.
If this doesn't help - leave a post in the Skype group and we will try to a video for you to watch. Many of us in this group monitor the skype group more than we go into the forums.