Start with ¾" plywood that is twice as wide as the depth of the cabinet and as long as one side and top/bottom. I crosscut the top and bottom off of one end and set it aside. Then, using a ½" dado stack in my table saw, I cut a series of ¼" deep dadoes across the sides. Make the spacing between them uniform so that the drawers are interchangeable. Finally, rip the sides and top/bottom in half to separate them and assemble the cabinet however you please. If you want to hang it on a wall, attach a French cleat to the back at the top and a batten of equal thickness at the bottom.
You can also use Google image search to research a project. Unlike the PDF search, the image search provides a photo of what the project will look like, which is helpful in determining if you want to pursue building it. By doing an image search for how to build a step stool, you will have a ton of options that all lead to woodworking plans of various quality. (The how to part of these is important—otherwise you’ll just get pictures of step stools.)