How to add players to groups

I have used groups before but not in a while. I looked into it today but can not see how to add players to groups for permissions within a game. Help?

I think group functionality has been broken for a while now. I remember using them before, but now even my old game which has groups seems to no longer have any players in any of them. Back in September during the big update, vagueGM also mentioned groups not working at all as well.

(I wish they worked.)