Push the ends of the second course into the sealant. Align the butt edge with the story-pole marks on the corner boards.
Nail the clapboard to the studs as in Step 2.
Follow the chalk line to align the butts. Stagger the joints as you work up the wall.
With a utility knife, notch the top of the board to fit beneath the window. (Save the scrap for Step 8.)