Once your download has started, click ‘Files’ to the right of the torrent you are downloading.  This will show all of the files being downloaded.  From this view, you can monitor the progress of each file download, or switch the toggle to the Off position for the file(s) you want to exclude.  Alternatively, once the files have finished downloading, click on the torrent in your Torrent Feed, then click Folder, which will reveal the files.