Place your first wall section in position and secure it to the floor and ceiling joists.
Move the second wall section in place against the first wall section. Clamp the studs where the walls meet together with several C-clamps, placing at least one near the top of the stud and one near the bottom of the stud.
Drill a series of pilot holes into the studs, 16 inches apart, from the inside edge of the studs.
Insert 4-inch wood screws into the holes and tighten to secure the wall sections to each other. Remove the clamps.
Secure the wall section to the floor and ceiling joists.