Kinda made it up as I went, with help from a couple friends. They're solid walnut, 2" thick, so they're very heavy. They need to be supported very well. So, what I did was to put 1/2" lag screws into the studs, then I cut off the head with a hack saw. Effectively then, I made solid posts sunk about 3" into the stud. They can hold a lot of weight. Next, I drilled 5/8" holes in the edge of the shelves, and slipped them over the lag screws. One of the shelves was a little loose, so I put a couple set screws in the bottom of the shelf. That's the only hardware that's exposed, but it's very minimal.

It was a little difficult, just because the lag screws have to be screwed in very square and very level. It takes two people for that reason. Also, the holes in the shelves have to be square. Other than that, it's pretty simple. Tools required are an electric drill, a chop saw (you could get away with a hand saw if you don't mind your arm getting tired, or you could have your hardware store cut them), a hack saw, a level, a socket wrench, and the various drill bits.

Here's a better daylight photo.