Mind helping a newbie?

I'm new to VR chat and I know NOTHHING about this game, it just got my attention since I could roleplay as characters from my favorite franchises. Everytime I tried to put on an avatar it said error (well for some avatars specifically), I also got the idea of entering VR chat due to YouTubers videos impersonating characters, and I saw some of them had avatars with custom animations. Would you kindly help me?

I'm new to VR chat and I know NOTHHING about this game, it just got my attention since I could roleplay as characters from my favorite franchises. Everytime I tried to put on an avatar it said error (well for some avatars specifically), I also got the idea of entering VR chat due to YouTubers videos impersonating characters, and I saw some of them had avatars with custom animations. Would you kindly help me?