Well, what you need to do first is update the system. Go to "system settings" then click "other settings". After that go to page 4 and hit the update button. To access your code afterwards..click on the orange smiley face at the top of the home menu.
That was EB Games on the phone. If I don't pick up my 3DS TOMORROW (not Saturday as we where told, TOMORROW!!!) I have to wait for the next shipment which is two whole weeks away!