A reliable installer such as DBI , Tinfoil , or Awoo Installer .

the extracted .nsp update file into that folder.

A tool that supports .rar archives, like 7-Zip or WinRAR . 2. Extracting the File

Navigate to (or "NAND Install" if you prefer).

Wait for the transfer to complete. DBI will automatically install the update and notify you when finished. Return to the Switch Home Menu. Highlight the Splatoon 3 icon. Press the (+) button to open Options.

If the game fails to launch after installation, ensure your Sigpatches are updated to match your current firmware and Atmosphère version.