Ok, to download torrents you need a client. I would recomment uTorrent, www.utorrent.com. Then to find the stuff to download you can go to a variety of places. Here are a few websites.
www.mininova.org
www.thepiratebay.com
www.btjunkie.org
I know mininova has the office. So you just search and find what you want to download, open the torrent with your Bittorrent client and it will download. You may need to open some ports on your router to get a good connections. If you need help with this or have any other questions, look through the Guides section of the uTorrent page.
Oh, one thing to remember, when you are choosing a file to download, look for ones with lots of seeders and leachers. You will get faster downloads that way.