I'm not 100% sure (since I've never created a group before) but, I'm pretty sure you just have to go to the gallery,and you have to look on the sides. There should be an add folder button. Then, if you need me too, I could tell you some folders we would need
I hope this is right. If not, you could probably look it up on the little deviantart search. There should be some kind of journal on how.