Once the base to the table is assembled and square, its time to attach the table legs.
First, cut the four 1x6's into eight pieces, each 35-1/4 inches long. This will make the finished table top 36 inches tall. (If a taller or shorter table height is desired, adjust your cut lengths in this step accordingly.)
With the table base flat on the floor, affix two of the 1x6 pieces in each corner as shown in the diagram above. Use a square to be certain that the legs are attached 90-degrees (square) to the base. Notice that one side of the leg is placed flush with the corner of the table, while the second side of the table leg overlaps the first. For extra strength, place a bead of glue in the overlap between the two pieces of the table leg. While adviseable, this is not a necessary step, because stringers between the legs will hold them in place in a later step.
Note: You might be tempted to use some 1-1/2 inch screws to connect the two halves of the table leg together. However, because of the lack of thickness of the stock, this may result in cracking or splitting of the piece being overlapped.