To keep the drywall dust away from the monitors, install the speakers first. Measure from the wall to get the horizontal placement of the two outermost speakers. Then, measure down from the ceiling for the height.
Slide the TVs into position. Use a rotary tool to remove any excess base on both monitors.
Slide the plasma screen back board into the opening and against the back stops. Strike the barrel bolts with a hammer to mark the frame, and drill a hole at each of the marks. Replace the back board and tap the bolts into the holes to secure it. Add a few extra screws around the edges.
Attach the bracket to the back board mount, and connect the cables. Slide the plasma screen back into the opening.