Confusion

I'm really confused about categories and forums. I thought that a category would set up a special box where forums could then be placed underneath, i.e. I have a Book Discussion category and under there will be the book titles and under that I will have chapter sub-forums where each chapter will be discussed.

But, when I look at my page, I do not see the category name showing up at all and the forums are all just listed one after the other.

Also, I do not understand "groups." Why would I need groups?

my forum is http://nnwforum.topicboards.com

Go to admin panel=>General=>Homepage=>Hierarchy and choose "Split categories on index :" or "Keep categories on index :" depending on how you would like your forum to look.
You can read a tutorial about Groups Here

Thank you!!!

You're welcome