the bittorrent file can be handled by ktorrent, open ktorrent and search for the mentioned file there, ktorrent will do the rest
if you are not in windows, other apps could handle the torrent, ares for example, can handle torrents very well, utorrent is another option
a torrent file is just a big text file with details on how to download form different places the iso file that is fullmonty
torrent is not the fastest way to download a file so be patient, this could take days depending on how many is sharing the file and the speed that is shared by those persons
it is easier for you to just click on this link
http://ftp.ch.debian.org/mirror/pclinuxos/live-cd/pclinuxos-kde-fullmonty-2011.09.isoit will be gin the direct download of the file, no torrent involved