Put on your safety goggles and head outside to a nice flat area. This is really the trickiest part - the rest it just a little tedious. :D
You're going to want to pick four-eight books to be the bottoms/tops of the legs. Doing both the top and the bottom in the way I'm about to describe will ensure your books are nicely compacted on the rod and make it easier to attach the legs to the table top.
I used milk crates as a drilling station, but you can also use two other books with a gap between them. (Image #1).
I didn't measure the exact middle of the books, I just estimated. I feel this makes the legs more interesting to look at, but if you're feeling extra particular feel free to mark the very middle of the book. :)
Now, follow the instructions in Image #2 to drill the books for the tops and bottoms of the legs!