Measure up 28 inches from the ground at the beginning and end points along the shingle-sided wall where you plan to install the handrail using a tape measure. Mark the measurements on the shingles with a pencil.
Pull a chalk line from one end point to the other with the help of another person. Snap the chalk line in the center to transfer the line onto the shingles. Remove the chalk line. The line on the shingles represents the line of the handrail.
Measure every two feet along the chalk line and mark the measurements with a pencil.
Position one handrail bracket at each pencil mark, one at a time. Drive the screws that were included with the brackets through the mounting holes into the shingle siding using a screw gun.
Center the handrail on top of the brackets. Drive the screws that were included with the brackets through the mounting holes into the bottom of the handrail with a screw gun.