*Remember, when using any chemicals, to use the proper safety equipment. Casting materials can be really, really bad for you if used without the proper protection.*
The first step was to draw out what I wanted to build, including the piece that I would sculpt and cast, in full scale. Once that was done, I made a copy of the drawing and taped it to a piece of plywood to use as a sculpting surface.
I used modeling clay to sculpt the piece, with beads added for certain details. Once the sculpting was complete, I built a plywood frame around it to function as a mold box.