Position a three-quarter-inch-thick treated MDF board on a work station or suspended between two boards. Drill holes all around the board, about two inches from the edge, spacing the holes every 6 inches. Use a wood drill bit that has a diameter slightly smaller than that of your masonry screws. Drill holes into the middle of the board's surface as well, spacing the holes in a 12-inch grid.
Position the treated MDF board against the wall in the desired location. Set a carpenter's level on top of the board to determine the straightness of the installation. Adjust the board accordingly.
Have an assistant hold the MDF in place against the wall. Push a masonry drill bit through each hole and drill for one or two seconds in each spot to mark it clearly. Remove the MDF and set it aside.
Drill more thoroughly into each marking using the hammer drill and making sure that it is on the hammer setting and its highest power option. Use a masonry drill bit that is visibly smaller in diameter than the masonry screws. Make the holes 2 1/2 inches deep.
Reposition the MDF board over the holes and set a 3-inch masonry screw into each hold to properly position the board. Drill each screw halfway into the wall until all the screws have been place to ensure that the board is correctly aligned. Set the carpenter's level on top of the board and check its straightness once again. Tighten all screws completely to firmly attach the MDF to the wall, being careful not to overtighten the screws.