please explain to me this exercise about the chain rule

Hello. In a few hours I have to take a test concerning derivatives, I understand almost everything, however I'm having a hard time trying to understand an exercise which is already solved in the book, this is the excercise

find f'(x) if f(x) = (2x^2+3)^4 (3x-1)^5

and so they solve the excercise, they apply product rule followed by the general power rule, but I'm so confused, I'm lost, I don't get it, i don't understand how they solve that excercise.

Could you please explain to me how to solve an exercise of that nature? please, with easy steps.

thank you.