There's no articles about KB priority (yet). In my experience, the bot will combind competing info into one answer. So if your PDF says the sky is green, and your website says the sky is blue, the bot will say something like "The sky is green and it can also be blue." For smalltalk, I'd recommend to do it in a plain text KB and just put stuff in there however makes you feel best. I've seen question-answer style like:

What is your name?
My name is helpful bot!

What is your purpose?
I help people!

I've seen a paragraphs of facts like:

Your name is helpful bot. Your purpose is to help people. When someone says "Thank you" you say "You're welcome."

I've seen bulleted lists of alternate responses like:

Thank you
* You're welcome!
* Any time!
* Happy to help!

and they all work just about the same. So whatever best fits your workflow is the best way to do smalltalk.