Ensure you have all parts (part1, part2, etc.) in the same folder before you start the extraction of part1.
The "paper" you are likely looking for refers to the or the RAR password required to extract the files. SBSP-BFBFR-NSwTcH-[BASE]-NSP-Ziperto.part1.rar
Use a modern extraction tool like 7-Zip or WinRAR to avoid "Header Corrupt" errors. Ensure you have all parts (part1, part2, etc