Missing files
So lately, I got the three files I need for the melonDS for my nintendo Switch; bios7.bin, 16KB: ARM7 BIOS bios9.bin, 4KB: ARM9 BIOS firmware.bin, 128/256/512KB: firmware
But I'm not sure where to place the files, and I put it in switch:/melonds but when I try run the emulator, it just keeps saying it can't find the files
The 'melonds' folder should be within a folder called 'switch' on your SD card (SD:/switch/melonds) and the file names must be exact. If everything is named correctly, it should work.

Does this look correct?
Rename "biosnds7.rom" and "biosnds9.rom" to "bios7.bin" and "bios9.bin" and you should be good to go.