The models include the Sun, Earth, Moon models shown in the images, but also include 8 coin-like representations of the 8 phases of the moon.
The holes in the model are designed to fit a 3/16" solid rod. I used a solid steel rod from home depot for about 2 USD and just cut it to my desired lengths. If necessary, the top and bottom of the Earth/moon spheres can be glued to the rod, but the friction fit for any of my builds has worked well without adhesive.
Print and assembly video can be found here:
https://youtu.be/QzC5bzUCHUI
The author marked this model as their own original creation.