I do understand that ease-in mean that the animation start slow, ease-out ending slow, and ease-in-out starting slow and ending slow.

But what is the meaning of the four values in the cubic-bezier?
w3school say:
cubic-bezier(n,n,n,n) Define your own values in the cubic-bezier function. Possible values are numeric values from 0 to 1.

But that doesn't explain much?

can anyone explain to me what is the meaning of every value in the cubic-bezier?