Actually, there is not just one puzzle to solve, but five.
First you have to download an application to the badge. It will be no problem, as all you have to do is to connect the badge to the USB port, hold power while you press reset, and the badge will appear as the disk named HackABadge. Just drag and drop the CHALLENGE.HEX file to that drive, and that's all. When you press the power switch on the badge, you're in the home screen, which is exactly as on the image.
There are four numbers and four buttons, which seems logical, but what about the fifth task? That's up to you to figure out. Not only that, but spend time thinking about how to attack every single puzzle, as they are each quite different.
Good luck, and have a good fun!