How to use bittorrent ?
First you download the program : http://www.bittorrent.com/
Then you click on the bittorrent links you can find on animesuki (for animes) or Dragonfly for doujinshis for exemple !
You click and chose your folder ! You choose "enter" and you just have to wait for the download to end !

Be careful because bittorrent reduce the BW (your computer runs slower)

But bittorrent is the best to dowload the anime so...