This is a Windmill or Windturbine. It designed it so it doesn't turn fast because in my region we have very fast winds. Therefore it's designed very tough.
For installation you need:
Then you put the nut on the threaded rod, then the bearings and at the top another nut.
After that you can slide the middle part of the windmill on that and glue the blades in the middle part.
You can also scale the model down if you want it smaller.
I printed my Windmill with PLA about 5 years ago and it's still holding up.