Its very simple. Visit t3nnis.tv (invite needed if you don't have an account PM me for an invite). Download this program http://www.utorrent.com/
and install it, then on t3nnis.tv go to the browse page. Use the instructions here http://www.tennis4you.com/forum/index.php?topic=13471.msg403457#msg403457
to find the match you want then click download and the torrent file should automatically open in utorrent. If it doesn't and you instead just downloaded the torrent file, go to where the file downloaded to and double click it, then it will open in utorrent. In utorrent it will then ask you where you want to save the file to, select wherever you want and click ok. This will start the file downloading, when the file has reached 100% you can right click the torrent in utorrent and select "Open containing folder" and it will take you to where the file downloaded.
IMPORTANT NOTE: t3nnis.tv is a ratio based site so you are expected to upload at least the same amount as you download so do not delete the match after you have finished watching it and do not close utorrent, you need to leave it open so people can get the game from you. If you fail to do this, you will eventually be warned and probably banned from the site for having a low ratio. If you have more questions please send a staff message on the site to get adbice about what to do.