CustomPress and using Custom Fields... adding a subtitle to 3Clicks

Howdy folks!

I'm setting up CustomPress on GameRageReviews.com and I would like to try to add a SubTitle to one of my custom Post Types.

3Clicks (3clicks.bringthepixel.com) offers Subtitles for its Posts and Works post types... so I was hoping to add a custom post type for Reviews using CustomPress and do the same (or similar).

I have next to 0 coding experience with WordPress so I would appreciate a little in-depth insight on how to achieve this.