Picture shows a slightly different version of the mounting plate, it was originally quite flexible.
Each hole should be drilled out with a 3mm bit before assembly so the joints can move freely. The split pieces scored and combined with superglue, and each joint is connected with a roughly 15mm section of 3mm steel rod. The joints are then capped off by manually extruding plastic into the hole. The wheels are mounted using the same technique, but with a washer on the flat side of the wheel.
Rubber bands are attached as shown in the picture. I like to use dental rubber bands, but any smallish rubber band can work.
The motor mount can fit most motors, but the suspension will only protect a 5 inch or smaller propeller
The ONLY place supports are needed are the rubber band hooks on the mounting plate, and the motor mounting holes