First, let's take a look at SpaceMonger in action. See the list of disks going down the left side of SpaceMonger's window? Double-click on the one near the top labeled "C:" and watch as SpaceMonger scans your computer's hard disk.
(If this walk-through window is blocking too much of your view of the action, you can move it around. Just click anywhere on this text with your mouse, and with the mouse button still held down, drag the window around until you can see what's happening in SpaceMonger's main window.)
After SpaceMonger finishes scanning your disk, click "Next" to continue.