This is a blog on ds homebrew and how to do it.firstly i do not encourage illegal activity.
Requirments 1.sd card
2.ds
3.data mangment on ds(get first time internet on it)
4.pc with sd slot
how to do it Get on your pc insert ur sd card then download the ds game or app move the application or game onto the sd card.insert the sd card into your ds go to settings data managment click on the game or app click copy copy this to your system.go back to dsi menu go to the end of the apps and your game or app is there to play.
THE END
i dont know.its like u download something on the computer like need for speed world.only u find a game that u like or wanna try and copy it to your sd card then put it on dsi from data managment.you can download games from btjunkie but you need to be careful you could put tons of virus's on your pc.for btjunkie you need bitcomet or utorrent.
you also need to make sure the game/app is for ds or dsi or it wont work.
you need to know what game you want though.i dont know any apps for dsi so u need to find some.
i cant i dont have an sd card but an example would be.go on any site find ANY ds or dsi game and download it or ANY app then copy to your sd card.then go to settings [after putting in dsi and turning on] then data managment go to sd card and click on the program copy it and go to dsi home area then click on ur app/game at the end of ur app/game list.