How does the procedural fauna work in the Boy with the Kite Demo?

I’m a little confused about how the fauna are generated in the boy with the Kite demo. Could someone be willing to provide a high level overview of the basic steps that they took. I know it’s a combination of blueprints and c++ and I’ve imported the relevant files and compiled successfully, but it’s not entirely clear to me how to recreate such a system for another project. If anyone has thoughts on how you would do this in a 3rd-person tutorial template that would be super helpful. Thanks very much!