It took me a while to figure it out, too, because I wasn't sure where exactly to paste the code.
Rightclick and choose "Inspect Element" in the menu that opens. In the upper left corner of the area that opens next, you'll see different options: "Inspector", "Console" etc.
Choose "Console" and then you'll see the white space Christi mentioned in her instructions. That's where the code needs to go.
Edited: Sorry, confused right and left.