First, You need to find a torrent server to download the file from. (TorrentReactir.to, thepiratebay.org, and Kat.ph, and isohunt are a few good ones....google it and find your own If you like).
When you visit any if these sites, just search for the torrent you want, and cluck download.
I warn you click the link that says download torrent , in the download details. Do not just cluck the first place you see "download", because many of these links are ads that will take you to third party sites that may cause spyware or adware on your computer.
When you click this, open the .torrent file in utorrent. Most browsers will do this automatically when the download finishes. The .torrent file is small in size, and should finish instantly.
Once you do this, tour download will begin. Just let utorrent run until it finishes.
A game like the Sims will contain a .ISO file, and possibly other files as well. Think of the .ISO file as the Cd Rom of the game that you would need to play the game. In order to install and play the game, you need a program that can mount the image to your computer, or make the computer think you inserted the disc. There are plenty of programs to do this( powerISO). Download and install the program.
Once the ISO program is installed, make sure it us running, and when your download is complete, right click on the completed file, select "open in containing folder", locate the ame ISO file. Right click the ISO file, and select "mount to drive g, or whichever drive shows" .
Now, go to my computer, Drive G, and run the installer, then.....enjoy the game.
Note that some games require a product key, a keygen to generate the key. The keygen, along with instructions should be included in the torrent folder(e.g. C:users/downloads/the Sims.
Good luck. I hope I didn't confuse you too much.