Instructions
Insert your SD card into the available SD slot on your Nintendo DSi.
Turn on your Nintendo DSi.
Open the "Systems" folder by selecting it from your list of folders.
Tap "Devices." This will show you any applications that exist on your SD card.
Select "SNESmulDS." Press "X" to run the application.
Select the game you want to play from the list of available roms, then press "X."