If the extraction stops and asks for the next volume, ensure all part files are in the exact same folder and named correctly.
Ensure Clash.II-GOG.part1.rar , part2.rar , etc., are downloaded into a single folder. Right-click only on Clash.II-GOG.part1.rar .
You need software like WinRAR or 7-Zip installed. Step-by-Step Installation Guide Download All Parts