Things You'll Need
Instructions
Download the .SAV file for your Nintendo DS game. Save the file to your desktop for ease of access.
Insert the MicroSD card into the USB card reader and connect the device to your computer.
Open the contents of the Micro SD card in Windows Explorer. You can open Explorer by hitting the Windows key and "E" at the same time.
Find the .NDS file that corresponds to your save. For example, if you downloaded a .SAV for a game titled "Monkey Business," you would need to find the "Monkey Business.NDS" file on the MicroSD card.
Rename the .SAV file so that it's an exact match to the .NDS file. Sticking with the "Monkey Business" example, your new .SAV would be titled "Monkey Business.SAV."
Drag the .SAV from your desktop into the same folder on your MicroSD card as the .NDS file.
Remove the MicroSD card from your computer and insert it into your Nintendo DS cartridge. Place the cartridge into the DS and turn the power on.
Load the game you want to play. Your .SAV file will be accessible on the game's load menu.