Thanks, Wayne! I wish I could read it, sounds like it would be a lot more interesting than the few hundred pages if constitutional law that I should be reading right now instead of futzing around on a Nikon forum! LOL!
By blur I mean everything is blurry. I was at a brewery taking pictures of their chalkboard, some displays, and the taps, everything was completely stationary and completely blurred.

I did buy a book that was recommended on here somewhere, the Nikon D3100 Digital Field Guide. Also bought an iPhone app entitled Nikon D3100 Toolkit for Dummies. I thought I needed to learn more about actually using all the settings in my camera before I started reading about exposure and composition. Maybe I'm wrong. :?
I can appreciate that you certainly must be busy there.

But you surely have a couple of hours now and then. Your Asheville area is so fantastic, it needs lots of camera attention too. I am not familiar with that D3100 guide, no doubt it is good, but suspect it is mostly about the camera menus, instead of about photography principles. It probably tells you how, but not why or when (your question). I mean, much of the menus are about little fine points, not about basic photography. Aperture, shutter speed, ISO and White Balance, those are basic photography. Both subjects are needed of course, there are lots of details, and more than one book won't hurt.

But you asked the question starting this thread, so I was trying to address that. I mean, you ask, so why not find out?
Maybe it is a little wrong, just in an incomplete sense, in that the menus won't help much until you know what you need to do to get picture you want. When you know why, then you know how. So this is about any camera, and it's all pretty easy, you just need to see it once to get the idea.
Please realize I am really trying to speak generally, to all beginners that have the same questions. There is some stuff that we just gotta know, to have a clue, to get much out of it. But its easy, we only need to be interested enough to find it.
There are lots of books on beginning photography principles, and I'm a little techie, and there always seems like there is more that could be said, so I might not consider this one was the very best one. I mean, it is a short and fast breezy read, admittedly good but not deep on anything, and not technical at all, how impressive is that? But speaking of impressive, its sales at Amazon clearly says I'm wrong. Read its user comments there, newbies eat it up as wonderful (helpful).
It is only 160 pages, letter size, but many many full page photos, and many very large photos, so I doubt it has even half that much text. Only 5 or 6 chapters,
1. Exposure
2. Aperture
3. Shutter speed
4. Light
and a couple smaller ones, about a few details.
It answers the question you asked, why and when. It is a review of the same principles you would get in an elective beginning digital photography course, about basics. But will be a lot faster to simply just read it once, a fast easy read, but then you'll know. And then of course, photography does need practice (thinking practice). Auto mode is not always the best thing.
Anyway, I hope that helps.