Calculate how many boards you will need to make the top.
Joint the edges.
Use the Biscuit Jointer to join them up.
Glue Using Bar Clamps. Use more than you think.
Next Day: Run through the planer to get to correct thickness making sure to clean up both sides.
Mark the center by drawing diagonals from the corners.
Draw your circle using a compass.
Cut out using band saw and disc sander.
Using the 2x4 - 90 degree jig clamped to the fence, router the top and bottom of your stool.