Here just a tutorial of what i had to do to install a primary and secondary boot drive, an upgraded 250gb Samsung evo 850 SSD drive sata III as the boot drive on a Korg Kronos 2 61 key and 73 key.
Cloning the drive will work without having to use the DVD's or reauthorizing it, but in case you do not clone the drive then the DVD's that came with your Kronos will need to be used by connecting an external dvd player to the usb port of your Kronos while the unit is off. Then once unit is on the Kronos will boot off the dvd drive and you should see 4 options on your Kronos screen.