Use the mouse to select the File menu item. From the drop down menu select Open.... The Open File window should now pop up. Select the file 1bit.strm from the Files box and then press in the OK button.
Carafe should now display the file 1bit.strm graphically on the screen. The file 1bit.strm is a cell for a 1 bit full adder.
Use the left mouse button to box an area to zoom in on. The right mouse button is used for centering the display about a selected point. The bottom three buttons can be used to zoom out all the way, zoom in, and zoom out respectively. Play around with zooming in and out using the mouse and the zoom buttons.