Gateway 3DS only works, and will only ever work on 4.x 3ds systems. You can't use a gateway 3ds on your system. As to your question as to how the gateway card works here's a quick break down - gateway 3ds comes with a blue card (cheap DS flashcard) and a red card (Gateway 3DS flashcard). The blue card runs the 1st in a 2 step exploit process. The first is called the "Mset exploit", and all the required files are on their website. After the Mest exploit, you get taken back to the system menu of your 3ds, you go to settings, other settings, profile, Nintendo DS - that will execute step 2, which will boot you into gateway mode (red card needs to be in the card slot). After that, press SELECT, and the loaded 3ds roms will pop up, pick one, and then start playing the roms. Any other questions, I'd be happy to answer.