Install it in the drive cage (w/adapter if needed)*, and then do a clean Win8 install to it if you want it to have the OS on it. If you just want it for a data/storage drive, just quick format it.
*Once physically installed, check BIOS at boot to see if it is recognized and that it is not set as the boot drive unless you want it to be. Then in Win, it will be automatically assigned a drive letter.