Hi there, and welcome to the forum.
Well, from where I'm standing "absolute beginner" and "cnc router" are pretty far apart from each other. I've made a lot of guitars, and I've had wooden parts made on a CNC machine, but for me making the leap to having a body made on a CNC machine would be a huge time investment in Solidworks to get the CAD model for the body. Unless doing CNC is your day job and you're really comfortable with it, I would say buy a body.
If you're hell bent for leather to do your own body, start with a warmoth body blank. At least the important stuff will be pre-routed alleviating you from that little problem.
The next thing I would say is to know your specs ahead of time. Go to your local nice guitar store, and try every guitar in the store. Figure out what you like. The neck is the main thing here. Once you've narrowed it down to a few guitars that speak to you, get out the callipers and measure that thing! Write it all down and find the closest warmoth equivalent. Also, construction and setup of a floyd equipped metal machine is going to be different from a hollow body jazz box. If you can tell us what you're looking for, we can offer some better tips.
The next thing I would recommend is to have the guitar finished by someone else. Finishing is one of the very hardest things to get right, and unless it was a simple oil finish, I always had trouble. Warmoth is the way to go here; their finish is top notch and it's actually reasonable cost wise.
Finally, the actual assembly of the guitar is straight forward. If you are at all comfortable with hand tools and drills, then you should have no issues. There is a lot of lore in the details (e.g. "wax your screws", "spin the drill backwards to centre it", "tape on the drill bit") that you will find perusing these pages. If you're stuck on one part, a local repair person can probably fill the gaps.
One last thing: Setup is very important. If you are doing this yourself, invest in some feeler gauges and a set of nut files, and a book on guitar setup and repair.
Have fun,