Firstly you need to purchase a seedbox from any seedbox provider to set up a virtual remote server. Now you need to set up a torrent client like rutorrent or deluge which will help you download and upload files. All this downloading and uploading of files is done on a remote server.
If you wish to transfer files from the seedbox to your local desktop then you will need a file manager like FileZilla that will help you to securely transfer files to your local desktop using protocols like HTTP or SFTP.
Many seedboxes provide technical support for setting up seedboxes.
At Iseedfast, The Setup is done for you by us.