Hi, I have a seemingly straight forward question but I seem to get lost half way through! how do I differentiate y=(4x^2 - e^2x)sin3x ?

So far, I think: let y = z.sin3x where z = 4x^2 - e^2x

then dy/dz = 3x.z.cos3x and dz/dx = 8x - 2e^2x

I know I have to then apply the chain rule but that's where I go wrong, can anyone help please? Apologies for the format.