Yeah, there are several user guides in the FAQ posts section (which is a subforum of this one), which should have all the information you need.
It seems like you've found it since you have run the firmware test. The firmware test basically tells you that you have a new ds that is
not compatible with magic key 3 unless you flash your ds firmware. I've outlined the procedure to follow here (Requirements Section, #2):
http://www.neoflash.com/forum/index.php/topic,1529.0.htmlThe basic idea is you have to buy a separate PassMe2 device in order to install the flashme firmware, thereby replacing the original one on your ds. It's not as complicated as before since there are utilities which streamline the process.
Just check it out and come back if you have any specific questions.
BruceG