Okay, here's the lowdown. First, you download a "torrent" from the Internet. Some good sites for this are
http://www.torrentspy.com and
http://www.thepiratebay.org. These torrents are not the actual file you want; they are just very small files which contain data ABOUT the file you want. Assuming you have BitTornado installed (
http://www.bittornado.com), you can open this torrent file, and BitTornado will launch. First, it will ask you to choose where you want to download the file. Pick a folder, and BitTornado will then automatically search the Torrent network for other people who are "seeding" the file you want (seeding is when you keep BitTornado open after the download it complete, and it allows other people to download the file from you) and other people who are "leeching" (downloading) the file you want (from whom you can download the pieces that they already have). If it finds such people, it will automatically begin downloading the file from them, and continue until the download finishes. Once it's finished, you will find the file in the folder that you picked earlier. If you like it, be sure to seed it, so other people have a chance to get it too!
-Omni