Choose your add torrent method by clicking it's title or use search box selected by default, just select the torrent(s) and click "Add torrent" button at the bottom.
Use this method if you don't know how to find torrent files. The searches will be done at the most popular torrent search engines. Add the files from the results with good "health" ratings, and remember that the best way to download a file at maximum speed is by adding several similar files and leaving only the one having the fastest download speed. To see the most popular torrents, just leave the search query unchanged and click on search button.