What do you mean by the lower shot and the main shot? What's the difference between them?

Use a split mirror to illustrate how the 1 scene will form. What percentage of characters and other writings are included in the camera to make a composition? What actions have you done? From which angle the camera should be cut in or taken out, how the camera itself moves, how long it takes to record, and so on.

The encyclopedia is very detailed. ...

In fact, in simple terms, it is to draw what kind of action you want this object to do in this shot and explain it. You can understand it as ... a simple cartoon.

It doesn't matter whether the painting is grass or not, because it's not how detailed it is, but the quality of the painting lies in the rationality of the composition, the movements of the characters and the scheduling of the lens.