Run a stud finder against the wall to locate the two vertical wall studs. Mark the locations using a pencil. Mark the width of the stud so you know exactly where you can install the mounting bolts.
Measure the distance between the two studs. Measure both pieces of wood and use a saw to cut them to the size of the distance between the two studs.
Measure the distance between the top and bottom mounting holes of the wall mount from the kit.
Place the first 2-by-4 piece of wood horizontally across the wall so the ends lie over the wall studs. Drill two starting holes through each end of the 2-by-4s into the wall studs. Insert the bolts into the holes and use a wrench to tighten them into the wall. Repeat this step for the bottom beam.
Install your TV wall mount onto the support beam.