I used to do 3D. A lot. I have a few leftovers from that era of my life, and I am still knowledgeable enough to follow along the cool stuff that's coming out of the race between GPU manufacturers (when they aren't competing over who mines cryptocurrencies the best 🙄).
It's always been super hard for me to explain how ray-tracing works, because it's a very visual thing and it seemed like it required a good deal of spatial awareness from the people I was trying to explain it to. But it was probably because I suck at explaining how ray-tracing works without showing it.
So, I was super happy to find a video that explains it all better than I always have. Enjoy, then download blender and have fun rendering stuff.