You could start with this
article on the Blog. My recommendations are a good, heavy tripod (it's windy where I am, so a heavy tripod that doesn't move is always useful...) and also a remote for your camera. That and a large enough memory card to take lots of shots.
And yes, I time my shots based on hearing the firework leaving the canon as it were. So when you hear it leave, open the shutter and then you can choose when to close it after you see the burst(s). Here are a few of my shots, the EXIF should be available for all of them as a starting point:
EXIF
EXIF
EXIF