The TTDS card by DS TT is a media cartridge for Nintendo DS similar to CycloDS Evolution or R4. The cartridge allows users to download software and media, and load it onto the cartridge using a MicroSD card (included with purchase). This makes downloading amateur-developed games and software for the cartridge an easy procedure. Once you download the games to the TTDS cartridge, you can run them from the main menu of the cartridge.
Connect the MicroSD card for your TTDS cartridge to the USB port of your computer using the cartridge's USB reader.
Open "My Computer" or "Finder" and select the MicroSD card, usually called "MicroSD," "TTDS" or "No Name". Right-click in the root directory of the card and select "New Folder". Right-click this folder and choose "Rename," then type "Games" and press "Enter".
Place Nintendo DS game files (identifiable by their "NDS" suffix) in the "Games" folder of your TTDS card. Many sites maintain lists of amateur-developed Nintendo DS games; two such pages can be found in Resources.
Eject and remove the card, then place it in the MicroSD slot of your TTDS card. Place the card in the cartridge slot of your Nintendo DS and turn the system on, then choose "TTDS" from the main menu.
Select "Rom" to bring up a list of available games. Navigate the list with the D-pad and select the game you wish to play by pressing "A." Return to the TTDS menu by pressing all six action buttons ("A," "B," "X," "Y," "L" and "R") for one second.
It's illegal to use media cartridges such as TTDS to run commercially-available games unless you own the original cartridge. Only download from sites offering public-domain or "home-brew" games such as those in Resources.