Add tutorials when Mob/Raid is added

I didn't know or understand the new Mob/raid that was added. I tried to do some research, which didn't give me the correct details on this addition to the game. Why isn't there more details or even a tourtial when new things are added. Thinking about giving up on Minecraft altogether because in the process of learning what this new Mob meant it totally ruined two of my worlds which I loved and spent many months on. Not happy about the way patches and new info is added and with no warnings of the impact of it to your game.