A Template for ARM Assembly on the Nintendo DS, need I say more?
Open Command line and run vasmNDS.bat (file location)
to compile your program on the DS, it will be built as program.nds
in the same folder as vasmNDS.bat
Special thanks to ChibiAliens for the tutorials in ARM Assembly and for the basis of the example included NDS_Hello.asm
https://www.chibialiens.com/arm/platform.php