Measure from the center of one vertical stud to the center of another vertical stud about 4 feet away. Cut a sheet of exterior grade plywood to this width using a table saw.
Attach the plywood to the studs using exterior siding nails. Position the plywood so the edge of the sheet covers half the thickness of the stud. Nail every 12 inches near the edge, attaching the plywood to the vapor-barrier-covered stud.
Continue measuring, cutting and nailing the plywood until you have fully covered the exterior wall.
Position the first wide board on your plywood wall. Space the wide boards so no seam will become visible between plywood sheets. Measure, mark and check the spacing before attaching the first board. Use a 2-inch wide scrap board as a spacer once you have determined your layout. Nail the wide boards over the plywood to create the look of reverse board and batten.