I somewhat understand the TCG raid bosses, but I don’t fully understand it. Can someone please explain it to me?
The Raid Bosses work just like Sword and Shield. Just like the games, you can have up to four people all trying to take down the boss, but each person brings 2 cards, but no Energy or Trainers. The boss can attack multiple times as well. However, the host picks cards from the boss attack pile to determine who it attacks and with what. Also, it takes 4 knockouts to lose. Side Notes- The Players always attack before the raid boss.
Once you get knocked out, you get a Cheer Card, which gives your teammates buffs. The Pokémon then revives next turn at full HP.
This guide also gives a very good explanation and includes some more things that are helpful and I didn't mention like Hp and attack calculations that I don't know how to explain among other things. I recommend reading it.