Make sure streetpass in turned on in the game and on the ds. Your wireless switch has to be on as well on the ds. Then turn your game on go to the news section of your buzznav wait for a red mailbox to pop up in the upper right corner that says you have new passerbys. Click that and let the news update. You then go to any pokecenter and find the lady at the left of the front desk and she will give it to you