Best guide for it is by TRaSH.

Equipment-wise, you’ll want:

• Lots of HDD storage. A 1080p movie is about 10GB so if you have an idea of how many movies/shows you want you can figure that out, but once you start I guarantee you’ll keep going so be sure you give yourself more room!

• A device in your network connected to your router and is on 24/7 — I use a Synology NAS, but you could use a Rasperry Pi or a PC that you leave on. It’s much easier if it can run Docker!

You can start with torrenting if you want it to be 100% free, then if you like how it’s going and want much faster downloads and better availability you can dip into Usenet — I spend under $100 on an indexer and provider.

The most basic setup uses:

• qBittorrent as the torrent downloader
• Radarr as the movie manager
• Sonarr as the TV show manager
• Prowlarr as the indexer manager
• Plex as the media server

Depending on how much you like tinkering with stuff, you can get into Usenet downloaders like sabnzb, requesting services like Overseer, notification services like Notifiarr… and more.

The easiest way to get going is with Docker and using docker-compose files when they’re provided in documentation.