I’ve literally just set this all up and it’s working now after some tinkering, so here’s what I found out. Assuming you have correctly configured the sonarr/qbitorrent api keys and credentials:
When you make a TV show request in Sonarr, it will automatically add the torrent to your download client (e.g qbitorrent)
qbitorrent will then download the file to wherever you specify (e.g. /torrents/completed)
periodically, Sonarr will scan that /torrents/completed folder, and if it finds the tagged TV show, it will either copy or hard link that video file to your specified media folder (e.g. /media/tv-shows)
JellyFin will do the same, periodically scanning your media folders to see if there are any updates
EDIT: also if you are using docker containers, make sure that Sonars native /downloads folder is pointed at the same external folder your qBitTorrent is downloading files in
no joke but i remember reading something about this aagggeesssss ago where a group of researchers modelled the effects of no more mozzies on the food chain and found that, because barely anything fucking eats them, their eradication would be negligible