If it is a "pre-installed" release, there may not be a setup.exe . In this case, you can often just find the executable (e.g., PCBS2.exe ) and run it.
Run the game via the .exe file. It is often recommended to right-click and "Run as administrator." Common Issues PCBS2.V.1.00.22-KIRIGIRI-GOLDBERG.CRACK.part1.rar
Paste and overwrite these files into the main game folder where PCBS2.exe is located. If it is a "pre-installed" release, there may not be a setup