First,
Download this design from Thingiverse.
Next, you will need to import the design into a Computer-Aided Design (CAD) program. We recommend
TinkerCAD, a free online app made for anyone of any age to modify 3D printable designs.
In TinkerCAD you can quickly change the size, add text, remove parts, or combine with other designs. Learn more about
remixing in TinkerCAD here, or more generally about designing
here.