copy arm9loaderhax.bin to the root of the SD.
copy the Luma3DS.dat from the mset-spider folder to the root of the SD.
copy the Luma3DS.nds from the msetfolder to the SD of your DS flashcart, and run it to install the ROP
To boot 3.x-4.x NANDs, you need to load FIRM from the SD card.
Download this file and rename it to firmware.bin, then this other file and rename it to cetk, then copy both of them to the luma folder.