This is rather a lengthy video, but it shares a lot of material that gives you just some idea of what is really going on.

https://www.youtube.com/watch?v=WsIi-k04Qik&fbclid=IwAR0m4JDTIpxfWFXR5_O5gt2o0liWbTl6wYSNGgvpJkscMElsa9inFoKKqOw