I would think that you should be able to go to the guild hall for whatever class you want to join the guild for, as that class, and ask the NPCs at the front desk.
Mikhalia: and FWIW, my posts are 95% helpful, informative, or funny.
Mikhalia: only 5% or less of my posts are utter crap.
Tyapex: 393 posts of utter crap...
Mikhalia: Sounds about right.