well M3 DS Real is very simple (at least I think so):

1) You download the system files here
2) You drag the system files to your MicroSD in a folder named "SYSTEM" (no quotes)
3) You make a blank folder called "NDS" (still no quotes) to put any clean ROMs (from official games) in
4) any homebrew apps just go straight to the root folder of the MicroSD, no DLDI or anything needed

that's literally all there is to it