I built this using 1x4 hardwood and pocket holes for attaching. A simple plate from Home Depot holds the TV onto the mount. Screw the mount into studs with lag screws. Attach the plates to the mount with 3/4" wood screws. Hook up the cables to the TV, then lift it up and over the horizontal braces. The plate keeps it from falling off. The small shelves on the sides are for computer speakers.
Note: Be sure there is enough clearance above the TV to clear the plate.