I'm really not sure where to put this questions. I tried searching but didn't see anything about this issue.

I have a friend who recently bought the game but when he started his character he chose Primal Excalibur (Legacy). I'm on Coeurl which is on Aether (I think). He's trying to make a new character to join me but he can't figure how to switch to Aether for his second character. How can he do this? We're both on the PC. Thanks.