Have a great Friday and weekend, everybody!
If you're not familiar with the reference, read up here.
Full disclosure: This is an absurd use of a pie chart. Therefore, the legend didn't appear this way on its own. To add the items to the legend the way I wanted them, I went to the Edit toolbar. I added a custom text object, dragged it to the bottom right, and added the text. The red and green boxes are rectangle objects. Once I dragged them to their proper place, I double clicked on each and changed their fill colors to red and green. The next time you want to add something to spice up your graph, keep these options on the Edit toolbar in mind!