Stain, varnish, or paint the handrail to match your home's interior before installing.
Use a stud finder to locate and mark the studs along the wall. Mark the studs approximately 36-inches above the stairs.
Place a level vertically against the wall at the front edge of the top landing. Measure straight up 36-inches and make a mark.
Place a level vertically against the wall at bottom of the stairs. Measure straight up 36-inches and make a mark.
Connect the mark at the top landing and the mark at the bottom of the stairs by snapping a chalk line on the wall. This will be the line where your handrail will be located.
Mark on the wall where each bracket will go. Place a bracket at each stud. Position the brackets at a height so that the top of the handrail will match up with the chalk line. Set the brackets against the wall, use a level to make sure they are plumb and place a dot on the wall for each screw hole.
Drill pilot holes into the wall for the brackets. Make sure the diameter of the drill bit is slightly smaller than the diameter of the screws. Screw the brackets to the wall.
Set and center the handrail on the brackets. Mark the screw holes where the brackets will screw into the bottom of the handrail.
Drill pilot holes into the handrail. Screw the handrail onto the brackets.