Combine 1/4 cup trisodium phosphate with 1 gallon water in a bucket. Dip a sponge in the mixture and swab down the surface area of the shutters, removing dust and dirt. Allow them to air dry.
Lay the shutters you wish to use side by side so they're touching. Measure their combined width. Their width should be around 80 inches. Add or remove a shutter if necessary, but don't worry about meeting this dimension exactly. It's better that your headboard be slightly too wide than too narrow.
Measure the height of the shutters. They should be at least 3 feet high; they can be higher if you like, for a more dramatic effect.
Run a studfinder along the wall, marking where the studs are behind the wall with a piece of chalk.
Turn each shutter over and drill in the top part of a flush mount with a handheld drill and 5 gauge screws in the center of the back of each shutter.
Draw a straight line with a piece of chalk half the height of the shutters above your bed. Drill the bottom part of each flush mount along the chalk line, in accordance with each wall stud.
Slide each shutter against your wall, allowing the flush mounts to interlock.