If you try to extract and get an "Unexpected end of data" error, you are likely missing part .001 or subsequent parts.
Do not rename the individual parts. They must have identical names (except for the numbers) for the extraction software to recognize the sequence. SS-JulSS-013_s.7z.002
You cannot "open" this file by itself. To access the contents, you need the complete set: If you try to extract and get an