This is the first in a series of "Photoshop Kindergarten"
Designed for the RAW beginner who owns photoshop but is too
lazy to learn it.
What you need to do then is enroll in:
Kindergarten for the Photoshop (almost) User
First lesson MASKS What are they? and What do they do?
http://microstockpix.com/tuts/masks2/masks2.html