Drupal e-Commerce Overview Newbie

Good Day To All,

I was wondering if someone can point me in the right direction. I am new to e-Commerce and I am planning to setup a site using Drupal with this functionality. I am familiar with Drupal but not with ecommerce. I just need an overview of what is needed to launch an online store. What else do I need besides Drupal and the e-Commerce Module. What security measures can I implement and etc. Any information or help is kindly appreciated.

Thank you,

Mark