Thanks tuanphan and Derrick.
Before I get to that, I have been busy writing articles the past couple of days. I think what I need to do is have multiple blog pages that are named as my three main categories and add category associated posts under each of those pages so they will populate with the assigned posts I am writing. I had them as blank pages which I cannot add posts to. That's where I was confused.
If it doesn't make sense to you, it does to me so I think I'm good for now. I really appreciate your offer to help.