Now that the initial electrical and drywall repair work on the already drywalled outer walls is done, the next step is to do the interior framing for the bathroom and utility room walls. I first had to cut away the ceiling drywall to expose the ceiling joists, to which the interior walls would be attached.
After that, I used a skills saw and a framing nailer to build an initial rectangle and slid / hammered it into place:
Once the wall was in place, I cut, inserted, and nailed in the other studs to complete the wall, and also nailed the wall into the ceiling joists. After that, I anchored the wall into the concrete using concrete anchors.