You cannot extract the contents from .001 alone. You must have all parts of the archive (001, 002, etc.) in the same folder before beginning extraction.
It is recommended to use the 7-Zip utility for Windows, or apps like Unzip One or RAR Lab for other platforms. How to Extract KIA.7z.001
Using 7-Zip, open or right-click the KIA.7z.001 file. You cannot extract the contents from
Choose "Extract here" or "Extract to..." in the 7-Zip menu. The software will automatically combine the parts and extract the final file. To give you a better write-up, I need to know: I need to know: