Next, we put a layer of adobe on top of the newspaper-covered sand dome. The walls of the oven want to be 3" thick, with the clay as uniformly distributed as possible.
What worked best for us was to grab hunks* of adobe (about the size of a brick and roughly 3" thick) and put a layer of slightly curved hunks all the way around the base of the dome, taking care to smush each hunk into its neighboring hunks, so there aren't any seams visible between hunks.
Then we stacked another layer of curved hunks on top of the first (now seamless) layer of curved hunks, building all the way around the circumference of the dome again. Again, we smushed the hunks together as we added them to the dome so there weren't any visible seams between hunks or layers. We repeated this process until we put a roundish hunk at the very top of the oven and smushed it into place, too.
Note that three firebricks will be protruding from the adobe-covered dome -- this will form the lip (bottom front) of the oven itself. Don't worry about an opening yet; you'll be carving that out in a few days, after the adobe has some time to dry out a little.
*Don't get too obsessed about the neatness of these curved hunks -- they may be more "blob" than "brick." The important thing is that the hunk-blob-brick needs to be 3" thick and moist enough that you can mold it as you're building, but dry enough that it doesn't dribble and slip down the side of the dome.