Open the setup.exe file from your download folder.
Since this repack includes a Bonus OST , ensure you select it during the setup if you want the music files. download-cuphead-v1-2-bonus-ost-fitgirl-repack
If your PC has 8GB of RAM or less , check the box that says "Limit installer to 2GB of RAM usage." This prevents the installer from crashing due to memory exhaustion. Open the setup