To utilize "part06.rar," it cannot be opened in isolation. It is a dependent file.
Extraction must always begin with "part01.rar." The extraction software—usually WinRAR or 7-Zip—automatically detects the presence of "part06.rar" and pulls the necessary data as the process reaches that segment.
Unless these files are being used to back up a legally purchased copy, downloading game archives via split RARs often falls into the category of software piracy, which carries legal risks and lacks official developer support.