Extract:
Locate .3ds files in the output folder. If none are present, check for nested archives and repeat extraction on those. 7z to 3ds converter
Verify file type:
If you have downloaded a file ending in .7z and you want it to be a .3ds file, you do not need a converter. You need an extraction tool. Extract:
Because a 7Z file is just an archive, the .3ds file you are looking for is almost certainly inside the archive. You cannot convert a compressed package into a game or a 3D model any more than you can convert a cardboard box into the item inside it. You simply need to open the box. Locate
A .3ds file is a raw Nintendo 3DS ROM image. It is a digital copy of the game cartridge. This is the file format that most emulators (like Citra) and flashcarts look for when loading a game.