Generally a lot of them you can get an invite from someone on Reddit or discord. A lot also open up for a week or so allowing people to register every year or whenever a major tracker goes down so the refuges can join. you can check places like Reddit /r/opensignups.

A lot of mainstream stuff is ripped already, the “ratio” on some is more if you download a torrent, they want you to seed it for x amount of time or seed it back x amount to the community. I don’t know of any that expect you to be ripping and uploading that way, it’s recommended but a lot have groups for mainstream content.

There are a few “elitist” private trackers that require “interviews” and stuff, but don’t let that scare you off 99% of them are all just grab and invite or sign up and seed back to community for the week or so minimum (preferably longer) and your good to go!