Stand two of the 29 1/2-inch pieces of wood on end. These are two of the four legs for your bar stool.
Apply wood glue to each end of one of the 16-inch pieces of wood, then put the 16-inch piece between the two 29 1/2-inch pieces at the top. The 16-inch piece is effectively the brace between the chair table legs.
Use the wood glue to attach another 16-inch piece below the first one, about halfway down the legs. This is additional bracing.
Use the hammer to pound nails through the outside of the leg into the bracing. This provides additional support, ensuring that the bar stool won't break when someone sits on it. Put a nail through each leg into each brace.
Repeat steps 1 through 4 until you have attached all the legs to each other with the 16-inch braces. If you were to look at your bar stool from the top down, you would see a square.
Attach the seat of the bar stool by using a thin layer of wood glue on the top of the bar stool, then placing the 18-inch square of wood on top. Use a hammer to nail in each corner of the seat top. Let the wood glue dry, and your bar stool is complete.