Download and install the official 7-Zip (Windows) or Keka (macOS).
If you are missing any numbered file in the sequence, the extraction will fail with a "Data error" or "Unexpected end of archive."
Avoid using built-in Windows "Extract All," as it often fails to recognize split .00x archives. Right-click only on the first file: DBALEX.7z.001 . Select 7-Zip > Extract Here (or Extract to "DBALEX/" ).