CSC means “Consumer Software Customization” or “Country Specific Code“. CSC is an essential component of Samsung firmware. It is an important part of the firmware binaries which contains many important data like customized settings, system configurations, localizations and geographic specific settings and data. This can be different for devices with the same model number as well, because Samsung can release devices with different CSC depending on the location and the carrier of the device. Samsung builds specific firmware for these carriers.
You will need to connect the device you wish to work with in ADB mode to access this feature. When the device is connected correctly and you choose the CSC Change, you will be able to choose from the list that is displayed.