Basically, it's a very, very wet dough that can't even be rolled out. You more or less pour it into the pan after it's risen once, and it comes out with nice big bubbles and a light but chewy texture. In my own words:
3 cups all-purpose flour (measured by dip and sweep, about 15 oz)
1 2/3 cups water (yes, that's one and two-thirds cups. Lots!)
1 1/2 teaspoons salt
Combine in stand mixer bowl, using the dough hook on low speed. Scrape down the sides and keep mixing until all the flour is incorporated. Let sit for at least 20 minutes. Sprinkle over the top:
1 1/2 teaspoons yeast
1 1/4 teaspoons sugar (seems overly precise, but that's what the man said)
Stir in with the dough hook as before. When it's well mixed in, turn the mixer on high and let it run until you get something resembling a dough rather than a batter, 8-10 minutes. It will come away from the sides of the bowl while the mixer's running, and then slump back when you turn the mixer off.
Grease your rising container with a tablespoon of olive oil, using a big rubber spatula. Scrape in the dough with your oily spatula, and drizzle another tablespoon of oil on top. Flip the dough over once to get it well oiled, then cover and let rise for 2 - 2 1/2 hours. It will almost triple and generate lots of big bubbles.
If you've got a pizza stone, preheat it at 450 F. I don't have a pizza stone (though I really should look into getting one) and so I set the oven at 500 and put the rack on the very bottom.
Grease a 13x18 half-sheet pan with 2 tablespoons of olive oil. (This was a little much, perhaps. Though I do like olive oil.) Scrape in the bubbly dough. With oiled fingers, pull and coax the dough out towards the edges and corners. It won't extend all the way in any case, but if it's resisting, let it relax for 10 minutes and pull it out again. Let it rise again for 10 minutes before baking.
If you're going to bake it as traditional pizza bianca, they suggest poking it all over with a fork and sprinkling it with a teaspoon of kosher salt. Put it in for 30 minutes, but rotate the pan at the halfway mark and sprinkle the top with chopped rosemary. When it comes out of the oven, brush it with olive oil. (I don't see much distinction between pizza bianca and foccacia, but just call it foccacia and people will probably make it disappear quickly in any case.)
I made it as a more typical pizza with toppings: I baked it untopped for 15 minutes, pulled it out, spread it with sauce and grated cheese and popped it back into the oven for about 8 minutes. Actually, I made two batches of pizza, one with only all-purpose flour and one with 2 cups whole wheat and one cup white. Both behaved approximately the same, though the white dough had bigger bubbles and the whole wheat kneaded up faster. Next time I might possibly add just a little less water or a little more flour, since I think my dough turned out just slightly more liquid than intended, judging from the photos in the article.