There are several ways to install new SATA drive on a personal computer.
First of all, let's assume that your desktop computer has no SATA interface. Then, the only way to install the SATA drive is to buy an additional SATA PCI card and connect the drive to this card.

There are many places, where you can get that additional card from online retailers. You should look on eBay or at a local computer shop. You could also get the SATA hard drive installed at a local computer shop, but this service would cost you some money.
The picture below depicts SATA PCI card:

This card needs a driver to function with the Windows operating system. The driver disk is usually supplied together with a card. This card is not exclusive in any aspect. It has a couple of chips and PCI interface, so it will fit in computer's PCI slot. However, this type of card is not recognised by bios, so it is not possible to boot the computer using a hard disk connected to this card. There is more expensive SATA PCI card that can be recognised by BIOS.
If your computer already has the SATA interface, then it is necessary to connect SATA cable to the motherboard and to the hard drive. SATA cables also can be bought on eBay, online retailers or at local computer repair shops.

Other way to install the SATA drive on a computer is to use USB connection and an external hard drive enclosure. This picture shows how the external enclosure looks like:

It has a SATA interface and an USB cable. If you want to save the space and have a laptop hard drive connected to the computer, there are special enclosures for the hard disk of a laptop. If you want to connect this type of Hard Drive to a personal computer, you should get an external enclosure with additional power supply. This Hard Disk needs an additional power source, because it is big and USB power is not enough.
It is also possible to connect the SATA Hard Drive through eSATA interface. You will need an eSATA cable to maintain that.