Things You'll Need
Instructions
Download an SNES emulator for the Nintendo DS to your computer, such as SNEmulDS, SnezziDS or SNES DS.
Right-click the downloaded SNES emulator file, and select "Extract Here" from the context menu. The emulator files are extracted to the download folder.
Remove the microSD card form your M3 flash cart, and insert it into a USB microSD card reader. Connect the card reader to a USB port on your computer.
Open "My Computer," and click the icon for the USB card reader to open the microSD card's folder.
Right-click anywhere inside the microSD card's folder, hover the mouse pointer over the "New" menu and select "Folder." A new folder is created on the microSD card. Enter "SNES" as the new folder's title, ensuring all the letters are capital.
Drag and drop the SNES emulator files into the "SNES" folder on the microSD card.
Drag and drop your legally acquired SNES game files -- often referred to as ROMs -- into the "SNES" folder on the microSD card.
Remove the microSD card from the USB card reader, insert it into the M3 flash cart and plug the flash cart into the Nintendo DS. The SNES emulator is now installed on your DS's M3 cart and is ready to use.