How to install QBittorrent for downloading torrents.

Open a terminal and run the following commands :
sudo add-apt-repository ppa:hydr0g3n/qbittorrent-stable
sudo apt-get update
sudo apt-get install qbittorrent

Note: If you have an issue starting Qbittorrent, try removing libtorrent-rasterbar6 through the synaptic package manager and then repeat the installation, i.e: 
sudo apt-get install qbittorrent