Farmhouse wall sconces is install like any other wall or ceiling lamp. Usually in place of an existing fixture on a wall electric field that is bound in the electrical circuits in your home. While only a qualified electrician should install or upgrade those circuits. The average homeowner easy to install wall sconce lighting itself. In most cases, you will control the light from a wall that will not replaced when you add the new fixture.
Cut power to the bathroom on the field box house. Remove the existing lamp from the wall electrical box. Use your screwdriver to take out the screws on the bottom. So you can access the electric field and wires behind it. The wires by turning away from the old wire nuts counterclockwise. Pull fixture free, leaving wires hanging out of the box.
Find the mounting bracket that came with your farmhouse wall sconces lighting fixture. It will be a flat metal plate or rectangular band with the screw holes in it that corresponds to the location of the screw holes on the front of the wall electric field. Placing the bracket to the box by means of screws that came with it. The wire ends of the box should still be available through the bracket.