Make two squares using the 14-inch pipes as sides and the horizontal holes in the 4-way connectors to join them together at the corners. The squares are the top and bottom of the stool.
Rest one square assembly on the floor with the vertical holes in the 4-way connectors facing up. Slide one end of the 22-inch pipes into the vertical holes. These are the legs for the stool. Align the remaining square assembly over the legs so that the vertical holes in the 4-way connectors will slide over the top ends of the legs. Press the square assembly down into place.
Remove the parts one at a time and apply PVC primer to the adjoining ends with the built-in applicator. Apply the PVC cement over the primer in the same manner and press the parts back together. Continue with this process until all of the joints are bonded together with primer and cement.
Center the 1-by-16-by-16-inch board over the top of the stool. This is the seat. Position one u-bracket in the center of each 14-inch top pipe on the under side of the seat.
Drive the screws that were included with the u-brackets through the mounting holes into the bottom of the seat with a screw gun to fasten the seat to the PVC assembly.