TwlNmenu is a tool used to manage installed software on the NAND. It can install programs in the TAD format (similar to the Wii's WADs) as well as boot and delete programs. TwlNmenu has three modes: NAND, SD, and CARD.

NAND mode

In NAND mode you can boot, delete, and get info for programs installed to NAND. Only user programs are visible (anything in nand:/title/00030004/). The controls are as follows: The top screen will display information such as the company code, game code, and sizes of the app and save data. NAND mode also displays the status of installed programs. This is shown by highlighting the program name in a specific color.

SD mode

SD mode allows you to select and install TAD files to NAND from the SD card.

Quick explaination of TADs

TADs are essentially SRLs (NDS ROMs) that have been packaged into an installable format. TADs are very similar to the Wii's WADs, sharing the same offsets and signing. A commit in TwlIPL explains the similarity by showing that TADs were derived from WADs.

TAD files are created with maketad from the TWL SDK. Only NAND apps such as DSiWare can be coverted into TADs.

Signing in TADs is very important when installing. If a TAD is not signed for the target console (eg. dev signing on a retail DSi) then TwlNmenu will fail. Anything created with the standard maketad will be dev signed and only work on dev units, though there is also a maketad_updater used for updater signing in Twl SystemUpdater.

Using SD mode

CARD mode