Ensure you have Npri_alpha045.part1.rar , Npri_alpha045.part2.rar , etc., in the same directory.
Ensure you downloaded this from a trusted source to avoid malware or ransomware. Npri_alpha045.part1.rar
Use tools like WinRAR, 7-Zip , or The Unarchiver (for Mac). Ensure you have Npri_alpha045