Bring your DS to any participating retailer and follow these simple steps.
Remove any games that are in your Nintendo DS and turn on the system.
On the main screen, select DS Download Play on the Touch Screen.
Touch the trial version you wish to download. (A list of available trial versions will be displayed.)
Touch Yes on the Touch Screen.
When this screen is displayed, the download is complete. (It may take some time for the download to be completed.)
You can enjoy this downloaded demo as long as your DS remains switched on.