Project 13: How do I install CapacitiveSensor Library on Mac OSX 10.8.5?

I'm working on project 13, the Touchy-Feely Lamp, and I'm having some issues with understanding the instructions: specifically, how to install the library. For one thing, I don't know what "unzip" means.

Can anyone rephrase the instructions to install CapacitiveSensor? Thanks!

Here's the instructions as they are in the book:

The most recent version of the CapacitiveSensor library is here:
arduino.cc/capacitive. Download the file to your computer
and unzip it. Open your Arduino sketch folder (it will be in your
Documents folder by default). In the folder, create a new di-
rectory named "libraries". Place the CapacitiveSensor folder you
unzipped in this folder and restart the Arduino software.

All solved!