This excerpt is taken from the link I provided you with earlier:
What is ADB, and how do I use it?
Installing ADB
"Aside from ADB, the other set of initials that you see with Android hacking is SDK. This stands for Software Development Kit. So yes, in order to root most devices, you’ll need to download the entire platform that developers use to create apps.
To get started, pick up the version of Android SDK for your platform:
Once downloading, extract the file to an easy-to-remember place on your PC. On Windows, we’d recommend installing it in your root (c

drive, in order to make it easier to navigate there via command line.
Now you’ll want to open the folder that you extracted the SDK into, and launch the SDK Manager (on OS X, you do this by executing the program ‘Android,’ which is located in the ‘Tools’ folder in the SDK).
After launching SDK Manager, you’ll see a list of optional packages to download and install. Find the one that says “Android SDK Platform Tools” (you may need to expand the “Tools” entry to find it). Once you locate it, check its box to indicate that you want to install it (choose “accept”

. Unless you want to develop apps, it’s safe to uncheck everything else (choose “reject”

.
After choosing “Install,” Platform Tools will be automatically downloaded, and you’ll be (almost) ready to use ADB."
The rest of the article goes into details about drivers, directories, and testing your ADB connection. If you aren't connecting through command prompt (the black box with white text) on your computer, you aren't using ADB.