The bulk of interaction between an administrator and Group Policy will be via a Microsoft Management Console (MMC) called the Group Policy Management Console (GPMC). Chapter 2, Group Policy Management Console (GPMC), is all about this console so we won't discuss it too much here, but the primary things to remember are that the GPMC is the place you will visit to both configure settings and filter where you want them to apply, and that you will be able to launch and tap into this console from many different places within your environment.
Here is a quick screenshot of the GPMC for your viewing pleasure:
