i have ubuntu as an OS and i installed deluge as the client but i cant find a tracker and when i go to for example kickass torrents to search for a video, the VLC program does not recognize it at all.
Be careful of what you download from that source because not all software or content is legal to share.
When searching for torrents, the seeds should be of interest. These are people that have completely download whatever is of interest and they are feeding the leechers. Leechers have part of it downloaded, but not fully. So if there is many leechers, but no seeders, the only way you would finish downloading it is if a seed decided to come on line (for example, he might of shut his computer off).
With this said, look for torrents with a good amount of seeders.
Sometimes when you download something, you will need to decompress it using a file extractor. I use 7zip because it can pretty much extract anything and it's free.
VLC should recognize the video after it's in its raw format (not compressed).
I believe Deluge stores downloads in your downloads folder. So go to the unity bar, open up your home folder, and click downloads in the left pane. You should find the video there.