How to understand 3d CSS animations?

Question

css

Good day, people. Who fumbles, consult, please, on several questions. No matter how much I rummaged in the internet, I saw a lot of examples, but I did not find a clear answer anywhere.
1) How the "perspective:" property works, and to whom to set it - always the parent, or you can set the element itself, or you can set it much higher in the hierarchy. Generally when it will work. And yet, in any case, it is necessary to register this property to work with 3d space.
2) In connection with what the "perspective:" property will work. That is, do you need to screw some more properties, or you can immediately write transformations like "rotateY: ".
3) Why do we need the property "transform-origin: preserve-3d". When this property needs to be written and in conjunction with what. What does it do, because everything seems to work without it. Will this property work without "perspective: ".
4) What does the "transform: perspective(xxx)" property do. When it is applied and in conjunction with what.

I will be glad to any response, even if you answer only one of the questions listed.
If someone sends code examples with these properties, where a minimum of properties will be written in conjunction with which they work, I will be grateful.