The software will automatically pull data from the subsequent parts to recreate the single, original .NSP file.
It looks like you're dealing with a specific archive file for for the Nintendo Switch. Since this filename format is common on ROM-sharing sites, SMT3N-HDR-(USA)-NSwTcH-NSP-Ziperto.part1.rar
You must have every part (Part 1, Part 2, etc.) in the same folder on your computer. The software will automatically pull data from the