If it from pulsedmedia, then the easiest way is to download it directly by IDM through clicking "access Data directory directly for HTTP downloads" at your welcome page
or u ganna need to connect through FTP and by FTP client and then either using the FTP client directly to transfere or u can copy the http URL of the file u want to download and then "Add URL " at IDM with ur username and password of the
seedbox
I ganna make u a tutorial video If u like
about the first question: u ganna choose the directory "on
seedbox" to which the download will be
then u ganna choose the torrentfile.torrent "on ur home PC" and then click add file, after a period of time(the time required for the torrent file to be uploaded from ur PC to the
seedbox) the file will be added to the rutorrent