Its very easy to do as long as you have a a free IDE channel. In most computers there are 2 IDE connections to the motherboard each one can handle 2drives, one as a master one as a slave. This means that most motherboards can support a maximum of 4 IDE hard drives (DVD drives, CD drives, Hard disks). Im have a CD writer a DVD-rom drive and a single hard disk on my computer meaning i have one spare channel. Open up your PC case and have a look at the cable that is currently connected to your hard drive(s) and CD drive(s). One of these cables should have a free connector on it, if they dont then you could have a problem.
Once you have found a free connector then you simply plug it into your new hard disk, attach a molex connector from your PSU and turn on the comoputer. You might need to change some bios settings to detect the drive but that depends on your motherboard. Then you will need to partition and finally format your hard disk.
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