Clean the surface where you intend to place the lath, using a sponge and a pH-neutral cleanser. Wipe away any dirt encountered on the surface, but don't saturate the surface with liquid as this could cause some warping. Rinse the cleaner off the surface with water, and then pat the surface dry with a cloth.
Use a tape measure to measure the surface where you intend to attach the lath. Cut the lath so it covers the surface completely with space added to the measurements to overlap the lath 6 inches along any horizontal seams, and 2 inches along vertical seams. Use a pair of tin snips to make your cuts along the lath.
Use a stud finder to locate any wall studs in the surface. Mark the location of the studs with a piece of chalk.
Attach the metal lath to the walls, beginning at a corner and extending to the opposite corner. Place the lath against the walls with the diamond pattern in the mesh positioned so that they point upwards. Nail the lath to the walls, using a hammer to drive noncorrosive 1 ½-inch galvanized nails through the mesh into the subsurface every 6 inches. Use wall studs for the placement of the nails as often as possible for additional security of the mesh attachment. Overlap the mesh before nailing through overlapping areas, and overlap the mesh 16 inches around corners before starting a new mesh piece on the new wall surface.