You need an N3DS remember, with no updates on cart (and a cart that has an acceptable update). Then you need to find the guide on GBATemp, aswell as Linux.
EDIT: ihaveamac posted here, he was the one who wrote the guide. You need Linux, and if you don't understand I suggest you just get Oot3D and a PowerSaves; smashhax requires a bit of knowledge about Linux (not too much)