This is a project that generates complete model rockets designed to get you up and flying faster and cheaper than purchasing kits. All necessary parts (other than parachutes) can be generated, including but not limited to:

Nosecones
Tubes
Payload sections
Tube adapters
Lugs
Fins, including NACA airfoiled
Nacells
Centering rings
Threaded engine retention
Staging
Boosters
Engine clustering

If a generated part doesn't make sense, it's probably meant to generate in vase mode (and there are many vase options present)

When in doubt, refer to the examples in the json file. I know that probably doesn't help when using the web customizer, but if you play along at home (using OpenSCAD), the examples can be useful. 

Models included with this project are not generated by it, but necessary for the parametric tube cutter imports. Make sure they are in the same directory as the .scad file of this project.

While main body tubes can be 3D printed when using enough thickness (to resist thermal meltdown), it is recommended to start with your own secondhand tubes (paper towel tubes, wrapping paper tubes, ULINE, you name it) as a good way to save time and money.

I apologize for the lack of detailed documentation. This project assumes you are familiar with not only model rocket components, but also have a good understanding of your slicer, i.e. if you can properly slice a 3DLabPrint airplane, you will not have too much trouble here.

That being said, I will attempt to address questions in the comments as time allows.