Your motherboard's BIOS will automatically detect that an extra HDD is connected to the computer if you connected the right cables to it, unless it's faulty. After it detects it you just boot up your PC, search 'Disk Management' and you can set up a partition for your drive. In Windows 8, searching Disk Management comes up with 'Create and format hard disc partitions'. From here you can extend the amount of space the drive can have, shrink it, split into multiple partitions or completely remove the partition (essentially wiping the HDD).