HTTPMail Plug-in

Hi:

I installed this plug-in a few days ago but just can't find a way to get it to work. Anyway, I've now decided to un-install it but there something I don't understand:

"How do I get rid of this thing?
1. To de-install the plugin, you must delete the httpmail.mailbundle folder in the Bun-
dles folder of the current user.The path is likely to be: Macintosh HD / Users / [cur-
rent user name] / Library / Mail / Bundles. You must also delete every http-Mail
folder that was created in the Bundles folder.
2. Then you must de-activate the plug-in by executing the following command in a
Terminal window, paying great attention to the exact spelling:
defaults write com.apple.mail EnableBundles 0"

This is the un-installation procedure... #1 is fine but I'm having trouble with the second step. And my question is... What is a "Terminal window"? Sorry if this sound ignorant but I've just got my first Mac, I'm still trying to get use to OS X on my laptop while using Windows XP on my desktop.
Any imput is welcome.

Go to Applications-> Utilities-> Terminal.

Paste in the above command and hit return.

The terminal lets you access the UNIX underpinnings of OS X and execute commands directly without a graphical interface. This used to be how all computing was done...

Nowadays you'll only need to use it for certain tasks...

Thanks!