Don't think I can go into too much detail naming sites for downloading etc
But the basics are
Find a site to download films, music, apps etc.
Use this for searching.
Install and use a torrent tool, such as bittorrent, utorrent or other software
on your PC, this will allow you to download.
You may need a video convertor installed too as the downloads can come in a few different formats
such as wmv, avi, mp4, flv and your computer may not be able to play all the various formats
Google "afdah" that may be useful to you
Finally, you may want to install a little program called "caffeine" it will stop your computer going into
standby while the film is playing, otherwise you have to keep knocking the mouse every now and again lol