First, you need to get a torrent client. There are many different clients available, but we recommend using uTorrent. Once you have installed and launched uTorrent, you can find the file you want to download. Websites like The Pirate Bay and KickassTorrents are good places to start looking.
Once you've found the file you want, click on the "Download" button. A new window will pop up, asking you where you want to save the file. Choose a location and click "OK." The file will start downloading.
Now, depending on the size of the file, it may take a while to download. You can see the status of the download by looking at the "Progress" column. When it's finished, the file will be seeded and you can check the "Done" column to see how many people have finished downloading it.