SMTP server Postfix folder?

Hi all

I'm trying to enable Postfix so I can send emails from dev sites in MAMP.

I found this link that talks about the Postfix folder at Mac HD > etc > Postfix

http://www.youtube.com/watch?v=ZRJSQjXGjOA

I don't have a etc folder in Mac HD.

Should I have a etc folder?

I'm using a MacBook Pro, 2.3 GHz Intel Core i5, OS X 10.8.3

I don't have a private folder

My Mac-HD is

Applications
Developer-3.2.6
Library
Resources
sw
System
Users