For a wood wall or wood door, you can drill two small pilot holes on the corner of your sign (inside the border in the corner is a good spot)
and secure the sign with small flathead wood screws (about 2 1/2 to 3 inches long) which go through the front face of the sign into the wood.This is the best way since if you ever remove the sign, damage to the wood and the sign is very minor and can easily be patched. The altenative is to use an adhesive on the back of the sign; however, if you ever have to remove the sign significant damage to the door (and sign) may occur.

For a brick, stone, or stucco wall, you can install the sign either of two ways. The best way (but not the easiest) is to drill two holes in the sign and stucco when the sign is placed correctly. While one person holds the sign, the other drills through the sign into and through the stucco, which is about 1 to 1.5 in thick. These holes should be drilled with a 5/32 in diameter bit (#2) used with preferably an electric drill. The hole must be smaller than the screw. Place the two holes in upper left and right corners of the sign inside of border where they will not be conspicuous . Buy two concrete screws at a hardware store (these are "blue screws" and are called Tapcon (or Kwikcon) concrete wide-thread screws. See http://www.bluetapcons.com/ for more info. Use 3/16 in diameter screw about 3 1/2 in long.Insert the screws into the holes in the sign into the stucco.You may wish to touch up the two screw heads with paint-we can send you some touchup paint if you wish. until the head is flush withn the sign face.. Use the flat-head phillips screw model which can be countersunk into the sign rather than the hex washer head model..
An alternative is to glue the sign to the stucco-much simpler but it may damage the Stucco and sign if and when you remove the sign. You can use Amazing Goop, available at most hardwares. I would use Marine or Lawn & Garden Goop( http://www.eclecticproducts.com/ag_adhesives.htm,) but other varieties will work about as well. Smear it liberally on the back of the sign thick enough to fill in dents in Stucco; perhaps three spots 3 inches in diameter in middle and 2 ends-you do not have to cover entire back of sign.Let Goop cure a little, 2-10 minutes, before you place the sign on the stucco. You then have to hold it in place tightly until the Goop dries- it may take 20 minutes or more .Make sure you place sign correctly first time, it is difficult to move it after pressed in place. NOTE: If you wish to remove the sign later, you may break it or peal off some of the stucco.