Yeah, it's kinda thick. I just use the big book to look up things I may not understand from the pocket guide, or Thom Hogan's Field Manual, (I think Thom's manual is even bigger than Nikon's full manual!). Thom Hogan's Field Guide is probably your best bet, if you can find one. The D700 is actually a very basic and simple camera, once you learn what the dials and buttons do. As I said before, I have two of them, each set up for a different purpose. One for night sky photography, the other for general shooting.
Here's some links that will help. https://youtu.be/HYv2MStJ66c https://www.kenrockw.../nikon/d700.htm
The Ken Rockwell link is a basic introduction to the D700.
The YouTube link is a 28 part tutorial, (each part is very short) on the D700 on what's what and what it does, how to set the menu, and what the dials, buttons, and levers do on the camera. It's really simpler than shown. For mine, I set the White Balance, (in the menu) to AUTO and let the camera do the work with that, (it's very good at it). You can set the ISO to AUTO also and not worry about it, though I use it manual in both of mine, (ISO is like film speed, the lower the number, the finer the picture quality, but you need more light, or slower shutter speed, or larger aperture, or a combination of all). For regular shots auto ISO will do you well. I shoot RAW 14 bit for top quality, but there are other options for different shooting situations, (check out the tutorials).
I started digital with a Nikon D5500, a consumer camera. I soon out-grew it, it produces great images, it's light, compact, but way too auto and actually harder to learn shooting manual than a D700. And it won't auto focus with the older AF lenses that don't have a built in the lens motor. For me, learning the D700 was a lot easier.
If you get one, we'll help you set it up to suit your photography. Look at our settings for photos you like and try them. Hey, I'm learning new things here all the time!
You'll be very pleased at what you can do with a DSLR, and the D700 is a quality machine you can continue to grow with.