Simple, you replace your torrent client with it. Instead of opening a torrent file in QBittorrent or whatever, you go to the "torrents" section and paste the magnet link/open your torrent file there. Then select "convert" and then you can download the torrent directly from their servers. It's kind of like a seedbox that everyone shares, so that you don't have to wait for seeds so long as at least one person has added the file to Debrid before.

Select the "premium offers" link to get started.