Things You'll Need
Instructions
Plug your flash memory in to your computer and open it up in Windows Explorer.
Copy the desired text file to the root of the flash drive. If your flash drive has drive letter "E:" then the path to the file should be "E:\yourfile.txt."
Unplug the flash drive after the copy and insert it in to your flash cart. Turn on the Nintendo DS and let it boot in to Moonshell.
Use the directional pad to navigate to the files on your card and select the text file with the "A" button. Use the Up and Down buttons to scroll by line, and the Left and Right buttons to scroll by page. To open the bookmark menu, use either the "X" or "Y" buttons.