To print an item you only need to drag it from the Finder; if the Quick Print window is closed, click or drag an item on its icon on the menu bar, then click on the print button.
To open the window you have to click on the Quick Print icon (red circle in figure 2) on the menu bar, or type the hot key ([ctrl][alt][P] by default); you can also use the system Service (see figure 3) available from the Finder and from all the applications whose selected information can be used by Quick Print.
