For this to work, all you have to do is go into tag mode and let your system run. Even if there aren't any other transmitting devices (like other DS or a Wii) around, you will eventually meet randomly generated artificial avatars. It's pretty random, so sometimes there will only be one encounter in one to two hours and other times there will be several encounters in half an hour. Those avatars work just like any real avatars and they will provide you with scratch cards, let you build your avatar sector down to 100 floors and you can get all available avatar parts from them.
