When I setup the *arr stack with docker compose the specific images I used are the Hotio ones which provide a very easy way to make sure qBittorrent and Prowlarr are both forced to be through a VPN (Prowlarr is an index manager for all of the other *arrs).

I found these 2 sites to be the most helpful: https://wiki.servarr.com/ https://trash-guides.info/

I’d probably start with Prowlarr here (wiki.servarr.com)

I presume they mean the green squares on their GitHub account.

No worries, shoulda gone to Specsavers ;)

Their post listed 5 other options.