You need 10 packages of 5-gallon paint sticks (30 large paint sticks total), 2 packages of 12-inch paint sticks (6 small paint sticks total), Aleene's tacky glue, Paint or Wood Stain, and a hand saw.
Glue three 5-gallon paint sticks together so you are left with 6 pieces of wood.
Glue three 12-inch paint sticks together so you are left with 4 pieces of wood (these are the middle "steps.")
Cut the curved edge off the 4 middle paint sticks ONLY.
Use wood glue or tacky glue to attach all the wood pieces together
Glue a 12-inch paint stick to the back of the ladder to connect the legs.
Measure to make sure the legs are level and each "step" is an equal distance apart and adjust as needed.
Let the glue dry completely overnight before painting or staining.
Use a staple gun to attach the legs together if your glue has issues (this is optional, my ladder held together without staples).