Finite difference coefficients are a way of figuring out how much something changes over a particular distance or time. Imagine you are trying to figure out how fast your toy car is going by measuring how much it moves over a certain amount of time. You might say "it moved 5 centimeters in 1 second, so it must be going 5 centimeters per second".
But sometimes you don't just want to know the speed at one particular moment in time - you want to know how the speed changes over time. Maybe your toy car is accelerating or decelerating, and you want to figure out how much its speed is changing. In order to do this, you need to look at how much the distance travelled changes over a specific amount of time - this is called the "finite difference".
But how do you figure out how much the distance changes over time? This is where the finite difference coefficients come in. The coefficients are a set of numbers that tell you how much the distance is changing over a certain amount of time. Think of them as a kind of "formula" that you can use to figure out the rate of change.
For example, let's say you want to figure out how fast your toy car is accelerating. You might measure how far it moves in the first second, and then measure how far it moves in the second second. The difference between those two measurements tells you how much the speed is changing over one second - this is the finite difference. But to make the calculation, you need to use a finite difference coefficient to convert the distance difference into a rate of change.
There are different finite difference coefficients depending on how much time and distance you are measuring. Some are better for figuring out velocity, while others are better for acceleration or curvature (a measure of how much a curve is bending). But no matter what you're measuring, you can use a finite difference coefficient to figure out how much something is changing over time or distance.