Smodysey-nswtch-[base]-nsp-ziperto.part1.rar -

: Since this is "Part 1," you cannot open it alone. You must have all subsequent parts (e.g., part2.rar, part3.rar, etc.) in the same folder. You then extract only Part 1 using software like WinRAR or 7-Zip, and the program will automatically pull data from the other parts to recreate the full .nsp file.

: A common abbreviation used by release groups to denote the Nintendo Switch platform. SMODYSEY-NSwTcH-[BASE]-NSP-Ziperto.part1.rar

Are you having trouble these specific files, or were you looking for a guide on how to install them once they are merged? : Since this is "Part 1," you cannot open it alone