Measure 12 inches out from the starting wall at opposite ends (image 1), make marks, then snap a chalk line over the marks. Place the starter plank against the wall, then measure the distance from the edge of the plank to the chalk line. Verify the distance is the same at several points. Align the board if it is not. Any gaps between the plank and the wall will be covered by baseboards and shoe molding. Some manufactures recommend pushing the first row against spacers that keep the planks away from the wall a small distance. Others advise nailing the first row to the subfloor. Follow the manufacturer's instructions. If nailing the first row down, use a pneumatic nailer to secure the piece in place. Lay a second piece in place beside the first and secure it with the nailer (image 2). Although you are floating the floor, these first planks have to be nailed so they won't shift as the rest of the planks are added.