1. Turn it on.
2. Go to "Mii Maker"
3. Click "QR Code/Image Options"
4. Click "Scan QR Code"
5. Scan the codes for the characters you want.
6. Enjoy, you now have the four official Nintendo 3DS Miis from Resident Evil Revelations.
Note: If you delete these Miis, you can't ever get them back, since it won't let you re-scan the code.