first you need a client to handle the .torrent files. I use Azureus, very customizable, it's found
here. Here is another one, Bit Tornado, it is very easy, pretty much no setup and it is found
here. After you downloaded and installed the client, they should open up fine but if they are not you may have to manually set your computer to open the .torrent files with your client. PM me if you need more help.