To use this update file, you generally need a modified Nintendo Switch or an emulator. Extract the .rar file to get the .nsp file.

Ensure you already have the Base Game (Bayonetta 2) installed. An update file (ending in 0800 ) will not work on its own; it must be applied to the existing base game. Bayonetta™ 2 - Tinfoil

This indicates the NSP file is compressed in a RAR archive. You will need a tool like WinRAR or 7-Zip to extract the actual .nsp file before use. Usage and Installation

Most users use homebrew tools like Tinfoil or DBI to install the update from their SD card or via USB.