Lay two 2-by-6 boards across the sawhorses. Make measurements on the boards with a tape measure and mark them with a pencil for the size you need to cut. The size you need will depend on the dimensions of the washer and dryer you are going to place on them. You will need twelve boards for the frames and six for the center supports. Cut the pieces out using a circular saw.
Place the 3/4 inch plywood on the sawhorses and make measurements for the size you need to make the tops of the pedestals. Mark your measurements with a pencil and then cut out the pieces with the circular saw. Measure and cut the sides of the pedestals out of the plywood the same way.
Assemble the supports by nailing together the 2-by-6 boards. Four pieces make one pedestal support and you will end up with six supports in all. Place two stacks of supports on the floor with threes supports on each stack. The openings should face the floor.
Install the backs on the pedestals first using a drill, screwdriver bit and wood screws. The supports should be one at the bottom, one at the top and one in the center of the back piece. Attach the sides to the supports in the same manner and then the tops. Place the pedestals in your chosen location and then have a helper help you lift the washer and dryer into place.