What does it mean 'currently under post moderation?'

Thank you.

Hello,

I'm in need of some serious help...

Trying to build my site but do not know how to

        1)take a banner code any code and place it on the site page

        2)Unpublish is this possible?  My website has the codes just sitting on the pages!!
   
It can't be this difficult....I've been trying to get this together basically by myself....just found out about www.gdi-made-easy.ws!!  This may have helped when I signed up...