Use a standard NSP installer like Tinfoil, DBI , or Gold Leaf to transfer the file to your console.
If you are playing on a PC, you can use emulators like Ryujinx or Yuzu to load the .nsp file. SAMSHWDN-(USA)-NSwTcH-[BASE]-NSP-Ziperto.part2.rar
Download all parts of the archive and extract them to get the single SAMSHWDN.nsp file. Use a standard NSP installer like Tinfoil, DBI