Press the "2nd" key and the "Draw" key at the same time. This will open the Draw menu, in which you can select from a variety of drawing modes.
Move the cursor, using the cursor keys, down to the menu item labeled "A:Pen." Press "Enter." This activates the free-form drawing tool and opens the graph window where you can make free-form drawings.
Move the pen cursor to about one-third of the way from the top of the screen and about one-third of the way in from the left of the screen.
Press "Enter." This turns on the pen tool.
Draw an eye using the cursor keys. Make a simple solid block of pixels for a simple eye. You can draw a more elaborate eye shape if you wish, with pupil, iris and eye outline.
Press "Enter" to deactivate the pen tool.
Move the cursor to the other side of the screen, to about one-third of the way in from the right side.
Press "Enter" to activate the pen tool again.
Draw the second eye the same way you drew the first.
Press "Enter" to deactivate the pen tool.
Move the cursor to the bottom half of the screen, to where you want to begin one end of the smile. Turn on the pen tool.
Draw the smile using the cursor keys. Make it an upward-sweeping arc that is symmetrical. Add a second arc to create an open mouth, and add teeth if you wish to complete the smile.