@Aquablade96 It's not about your trainer card if you open your menu an option for Pokegear will appear through there an option for Online play will appear, which prompts 'save game y/n' hit yes and it takes you to anther screen which has the options Login/Register/Options/Cancel, what I need to help you is that username My User here is StarryDreamerKitten however my in game name is Ikuto or Jack or Sky but my trading user is Snorlax. this has nothing to do with the in game name it requires your online trading/battling name.
Do you follow?