"Finder" is the program that shows you your hard drive on a Macintosh. Its icon in the Dock is a blue smiley face. Finder presents a graphical method of browsing your hard drive just like Windows Explorer.
The easiest way to make a new Finder window is to start by clicking on Finder's icon in the Dock. Finder's icon is always on the far left. If no window is open already, a new one is created. Clicking on Finder's icon also brings it to the front.
If a window was already open and you don't want to disturb it, go up to the File menu and select "New Finder Window".
A new Finder window is also created if you double-click a folder on the desktop.