Installing a save file is not as simple as dragging and dropping on a standard 3DS. You need homebrew access. Here is the standard workflow.
Downloading and using MH4U save files is relatively straightforward: Mh4u Save File Download
: Return the SD card to your 3DS and use Checkpoint to "Restore" the selected save. For Citra / Azahar Emulator Installing a save file is not as simple
Because MH4U save files are user-specific and encrypted, they aren't often hosted on standard gaming sites. Instead, they are shared within community forums: they are shared within community forums: