Shiplap is rounded, wooden siding that provides an attractive wood finish on the outside of a house. The top edge is always thinner than the bottom edge, and most shiplap boards are about 6 inches wide. Overlap each board slightly as you install the planks, bottom to top.
Inspect the exterior wall to make sure all exterior sheathing (plywood,) vinyl vapor barrier and windows are correctly installed. Inspect all vertical pieces of trim, especially the corner trim.
Lay a bead of clear (or white) silicone caulk along the outside edge of the area you will cover with shiplap siding. Lay a bead along the bottom border, and caulk all window and door frames. If the bottom of the installation area hangs off the bottom edge, skip the bottom border.
Mark all studs before you nail the siding.
Nail the bottom row of shiplap boards with ribbed (galvanized) siding nails. Each stud should get two or three nails per board, placed in a neat, vertical row. Drive each nail so the head is flush with the surface of the board. Cut each end of the board square with a carpenter's square and circular saw.
Chalk a line from one end of the first board to the opposite end on the same row of boards--about 1/2 inch from the top of the board. This will create 1/2 inch of overlap on each row of boards. The chalk keeps each line of boards straight and even with the bottom edge. Continue caulking with the clear silicone along the sides, and around windows and doors, as you go.
Continue nailing boards in an upwards direction. Chalk a line after you complete several layers of boards. The last, top board should be fully exposed; caulk it on the top edge, as well as the two sides.