A torrent is a file, you go onto certain sites like these listed below...http://extratorrent.com/hot_torrents/http://www.torrentday.com/
You use a program called utorrent, simple to use and takes up very little ram, there are other programs but I find this one easier to use.http://www.filehippo.com/download_utorrent/2253/
Now to get the best speed when downloading you need the torrent who has the most SEEDERS, on our Talktalk connection we can have a 1gb movie in around 20-25mins.
Now some people swear by using piratebay and the likes but since mininova was taken down I got an invite to a private tracker site, you get 1 chance to join and have to seed the films, not just download then delete the torrent.
PM me if you need any help.