I want you to think of functions as machines! Let's start with one function, and we will call it f. if we were to plug in x to the machine, x would be an input. Let's say we get 1 everyone we plug in x to the f machine. This would mean the 1 is the output! f(x)=1
Now let's talk about composite functions! Let's say we have TWO machines, f and g. If we plug in x to the f machine, then we would get 1. If we plugged that 1 that we got as an output from the f machine into the g machine, then we would have g(1)=5. THIS is how a composite function works. g(1) is actually g(f(x)) because f(x)=1.
I REALLY hope this analogy helps you out! I apologize if it doesn't, however I've noticed that many people have had success in thinking about functions in this way!
If you need more elaboration, feel free to message me!
