Lay two 2-by-4 inch boards side by side on the floor. Measure 1 1/2 inches from the edge of each board and make a mark there. Line up a carpenter's square with the mark. Hold the square so it runs perpendicular across both boards. Trace along the carpenter square's edge with a pencil. Place a large X on the end of each board between the edge and the pencil line.
Measure 16 inches along the boards from the same end and make a line across both boards. Measure 1 1/2 inches over from this line and make a second line. Place an X between the two lines on both boards.
Measure 32 inches along the boards from the same end and make a line across the boards. Measure 1 1/2 inches over from this line and make a second line. Draw an X between the lines. Continue along the boards' length, making an X every 16 inches.
Measure 1 1/2 inches along the board from the opposite end and make a line. Place an X between the line and the boards' edges.
Mark the wall's location on the ceiling joists with a chalk line. Line up the top plate with the chalk line, marked side down. Hammer 3 1/2-inch nails through the top plate and into each ceiling joist.
Hang a plumb bob from one of the top plate's ends. Place a mark on the floor where the plumb bob's end indicates. Repeat this step on the top plate's other end. Snap a chalk mark on the floor between these two marks.
Line up the bottom plate with the chalk line. Hammer 3-inch nails through the bottom plate and into the subfloor. Space the nails 16 inches apart.
Measure the distance between the top plate and the bottom plate. Transfer this measurement to as many 2-by-4-inch boards as there are X marks on the bottom plate. Cut the boards to the appropriate length using a circular saw.
Line up one of the board's top and bottom edges with the first X marks on both the top and bottom plate. Hold a level against the board and make any necessary adjustments.
Hold a stud-framing clip against the board and the top plate. Hammer 2-inch nails through the stud-framing clip's nail holes. Do the same with a stud-framing clip against the board and the bottom plate.
Repeat Steps 9 and 10 with the remaining X marks on the top and bottom plates.