Apply base coat (use top coat if you don't have base coat) and let dry.
Add a stripe of bright red nail polish on one side of each nail. The stripe should cover 1/4 - 1/3 of nail.
Next, paint a stripe of bright orange, making it overlap a bit on the red, but not so much that you can't see the red. You also need room for 4 more colors!
Continue with yellow, green, blue, and purple. There should be plenty of room for each color, although I found that in order to make that happen, I had to overlap on each color. Use a thinner paintbrush if preferred:)