Align the angle brackets so that they are flush with the top of the pole, so it resembles a T. Mark the locations of the bracket screw holes along the pole with your felt tip marker. Remove the brackets. Drill holes that correspond with the screw holes, straight through the poles. Place the angle brackets back in position. Use your 3/4 x 2-inch bolts to secure the brackets to the pole.
Place the top surface of the angle brackets against your sheet of wood so that it is centered and approximately 1 inch down from the top edge of the wooden sheet. Mark the location of the screw holes and remove the brackets.
Drill corresponding holes in the wood. Place the brackets against the wood and use your 3/4 x 1/2-inch bolts to secure the wooden surface to the brackets.