Welcome officially @Rhue_Hyngwar!! You don’t have to start here or even introduce yourself but we usually recommend it as this place can be very confusing! 
As you’ll probably know @Sellalellen is the thornmouth leader so you can ask her questions as well as any of the Wagoneers! There’s also the Q&A thread you can check out as well!
When you’re ready you can introduce yourself to your fellow guild mates in the thornmouth welcome thread!
EDIT: Also I believe that somewhere on here it explains how you can join the thornmouth guild. It gives you a little tag and a guild badge next to your name! If I can find the darn thread I’ll link it!