N Card huh? My friend has one....
Basically, N Card is a slot 2 flashcard, with worse GUI than R4, and that's saying something.
I'm pretty sure you got a slot-1 cart and a slot-2 pak for this N Card. look closely at the nottom of the slot-2 pak. See a USB port there? That's your gateway to ROMs
Anyway, connect your N Card to your PC, boot N Card and choose USB Mode, now you can see the insides of your N Card via your PC.
N Card supports drag&drop if memory serves, which is good, so after all that hush about placing ROMs, simply Safely Remove Hardware and detach N Card USB Adapter from your PC
Boot it up, and look for your game and start playing!