To build the walls, Stephen came up with a little framing plan on paper so he would know just where all of the boards would be. He drilled (I think) a treated 2x4 into the concrete around the outside of the slab, and then marked the tops where the studs would go with a tape measure and a carpenter's square. Then he cut and laid out all of the pieces needed to build a wall section, and marked where each board would be connected.
The walls were built on the ground and then pulled up into place by the two of us. Each had a bottom board, a top board, and studs 16" on center. As we pulled the walls up, each had to fit over a bolt that had been set into the concrete before it dried. We put nuts over the bolts and tightened them. The long walls were put up in two sections.
The sections of wall over the doors are called "headers," and they were sections of 2"x12" glued and nailed together with a bit of plywood sandwiched in-between. The headers rest on vertical 2"x4" pieces that are screwed into the framework.
We checked for square. Top wall boards (2"x4") went up over the walls we built, and overlapped each other at different points than where the sections came together, to stagger the joints.
Part of the sheathing was put up to add stability to the frame. Cut-outs were not made for windows or the smaller doors at this time, though they were framed.
It was my birthday that previous Thursday (Aug.26th) so Stephen's mom and step-dad came up to see me Friday night. They helped build and pull up the first wall!