Note: Stone veneers come in boxes of flats (measured in square feet) and pre-molded corners. These can be purchased at major hardware stores. The veneers look like real stone, but they're made by pouring a mixture of cement into stone-shaped molds. These molds are individually airbrushed in different colors to give them natural variation.
For exterior wood walls, first create a moisture barrier. Do this by applying roofing felt or house wrap over the surface with standard nails. For masonry walls, this step is not needed.
For the mortar to stick to the surface, attach a metal lath to the wall with nails or screws. For masonry walls use masonry nails or screws.