The chain rule and compound functions

Compound functions:
A compound function is a function that is formed of two or more functions, where one depends on the other, behaving like a chain where each link is a function that is within another one and this is contained as well in another one and so on, to derive these compound functions we began from the most internal function to most external, considering that the following one always is going to depend on the previous one.
to derive the compound functions we must start by deriving the the most internal function until the most external , or by the simplest one until the most complex.