This project is meant to be cut out of 18mm baltic birch plywood + 6mm for the sitting panel. If your plywood is thinner or thicker, you will have to adjust the drawings on Illustrator or similar program.
You can find the SketchUp and SVG files up here.
Carve all the parts
Clean the tabs and file off the rounded areas of the joinery as seen on the video.
Glue the parts together.
Sand everything smooth and screw the sitting frame.
Apply finish to the wood parts.
Spray glue 40mm thick foam to the sitting panel, cover it with polyester batting and staple your fabric around to make the cushion.
Your stool is ready to use!