Pasting from my reply to a PM I just received:
You need a client, provider, and nzb indexer.
I use SabNZBD, Eweka.nl, and nzbgeek. It’s about $70/yr or so for the two subscriptions.
You will configure the download client to use the provider for its connection, but the nzbs you download will tell your client which messages contain the files.
You can search the indexer and download files that way as if you were using a torrent site. But it is really smooth and easy to use with sonarr or radarr fetching things for you. In that case, you would configure those fetchers to log into the indexer to search then send the NZB to your client automatically.
I feel like it’s been memory holed, but I remember 00’s flat earth being genuinely smart people using it to illustrate the ridiculousness of teaching creation beside evolution, which was a push around that time. It was a Church of Satan style mockery, but I guess the arguments were too convincing.