UBB.threads PHP Forum Software Community Forums UBB.threads Version 7/8 Support Sub topics/forum

I might be missing something. I did try to search this but I could be using the words.

I am using Version: 7.5.9 of threads.

I would like to have the ability to have a category like TRUE STORIES. Under that, Stories about Hiking. Then under that, Hiking Yosemite and several other subforums. Under EACH of the subforums I need to have the ability to make another subforum.

How can I go about this?