How do I use the "Burn-After-Reading" feature?

You can set messages to automatically self-destruct after they have been read by the recipient. Available timeframes include: "Burn Immediately," 10 seconds, 5 minutes, 1 hour, 3 hours, 6 hours, 12 hours, 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, 1 week, 2 weeks, 3 weeks, 1 month, or you can choose to turn this feature off.