If you prefer not to install software, you can use web-based tools to extract the files for you:

Alex imported model.3ds into Blender , 3ds Max , or Autodesk FBX Converter . No conversion from 7z to 3ds was needed — just extraction.

7z to 3ds converter

7z To 3ds Converter Online

If you prefer not to install software, you can use web-based tools to extract the files for you:

Alex imported model.3ds into Blender , 3ds Max , or Autodesk FBX Converter . No conversion from 7z to 3ds was needed — just extraction. 7z to 3ds converter