go to the r4 card's official website. the instructions there are written in a chinese accent but is easy to follow. there isn't much to it - you place the latest R4 kernel onto the microSD (sdhc) card. then you need nds homebrew...
you can find heaps of ds homebrew on the net...
plz note game (music, video, s/w, etc) piracy is never condoned. so, don't bother asking where to get your hands on free ROMs (in the form of .nds file extension) here.
google - and you will find the answer smacking your face like a common household brick....
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