In the 7z file, extract the "_nds" folder from both the 7z root and the "DSi&3DS - SD card users" folder, to the SD Card root. Merge folders, when asked to.
Extract the "boot.nds" file from the "DSi&3DS - SD card users" folder, to the SD Card root.
Extract the "cia" folder from the "3DS - CFW...
btw i feel this a good time to remind you guys that sea of thieves was made by rare, who also made DKC1-3 and DK64, alongside banjo kazooie and conker's bad fur day