How exactly do I go on about transfering my modded SD card to an unmodded 3ds.

Since my older 3DS kinda did a not so good thing, I bought a new one, unmodded. I still have the SD card from the modded 3ds. Since their both from Japan, I had to region change the 3DS to english, and now I have to do the same for the current one. What exactly is the gameplan here?