I know some calculus:

The chain rule is basically when you have a function INSIDE of a another function, for example if you had:

SIN(3x)

You would find y' of the sin, which is COS, and then you would find the y' of 3x, which is 3.

So you would get, COS(3x) * 3. Get it? Basically you just find the y' of the outside stuff (Sin) and then multiply it by the y' of the inside stuff (3x)...

BTY, in case you don't know, Y' is notation for the first derivative...

As for doing it multiple times in one problem, its easier than you think...

So, if I had Sin(3x) +/*/- or divide, whatever, you just need to know your rules for each one (product, quotient, etc.), you just do the chain rule on each one, then apply whatever other rules you get for the product...