Lay your 14-inch boards horizontal, parallel and 9.5 inches apart to provide enough space to lay each of the 16.5-inch boards across two of the 14.5-inch boards. (The 14-inch boards are actually 3.5-by-3.5 inches, which is standard for all 4-by-4 stock lumber.) Use the countersink before you screw one 16.5-inch board perpendicularly to the first two 14-inch boards. You should be driving three evenly spaced screws 1.75 inches from the 6-inch ends of the 16.5-inch board. The row of screws should be parallel with the 14-inch board and along the center of the 14-inch board. The 16.5-inch edge should be flush with the 4-by-4 ends of the 14-inch boards, not screwed onto the 4-by-4 ends. Repeat these actions with the other two 14-inch boards and the other 16.5-inch board. Use your countersink for all screwing applications.
Stand both sets of 4-by-4 boards on end, so the 16.5-inch boards are on top, parallel and 15 inches apart. The 14-inch boards should be between the 16.5-inch boards. Screw three of your 28-inch boards to the edges of the 16.5-inch boards so the 28-inch boards are parallel with each other. There should be one board on each end and one in the center. The 28-inch boards should be centered lengthwise, allowing 5 inches of overhang from the 16.5-inch boards on both sides of the table. The 28-inch edges of the outer two boards should be flush with the 4-by-14-inch edge of the 4-by-4. These boards create the tabletop.
Screw a 28-inch board to the 4-by-4 boards. The 28-inch edge should be flush with the table top. The ends of all the 28-inch boards should also be flush. Repeat this step with your last 28-inch board on the opposite side of the table.
Screw through your 19.5-inch board into the ends of the 28-inch boards. The 19.5-inch board should be flush with the tabletop and sides. Screw another 19.5-inch board to the opposite side in the same manner.
Fill the countersunk holes with the wood putty, and let dry. Sand down the entire project with medium-grade sandpaper, then with fine-grade sandpaper. Apply your wood stain, and let it dry.