The first step is to 3D print the cart and the two wheels. You can do this at the TechShop if you are near any of its 7 locations (http://techshop.ws/locations.html). I have included in this step the stl (stereolithography) files for the chassis (cart.stl) and the wheels (wheel.stl) you should print the wheel file twice so you have two. If you haven't taken the 3D printing class at Techshop, you'll need to do so before using the 3D printer. I used replicatorG to get the files ready to print.