I used the wiki on r/usenet, which was pretty helpful.
From my understanding, you need 3 things:
Usenet Provider (these are servers that host all of the content - you pay them to have access to download the content)
Indexer (this is kind of like Google but for the usenet providers - they will find and give you the .nzb file which will be used to access the content from the usenet provider above - you pay the indexer for their service)
Usenet client (This would be akin to a torrent client like Qbittorrent - it is the program which you use to download the content from the provider, using the .nzb file provided by the indexer)
Benefits of Usenet I believe are the high speed of downloads, generally accessibility to older and more niche content, and ease of use. You don't need to fish through torrents hoping that the seed/peer numbers are enough to actually get all of the content in good time.
I've found a lot of stuff there lately that I have not been able to find via torrenting sites, but are important childhood media to me/my wife.
Usenet is hurt a lot by takedown notices unfortunately. So lots of older popular stuff doesn't work. That said, things like Anime or something that isn't given a takedown seem to be on there about forever. The server speed is a benefit for sure.