Thanks!
I recommend setting the ISO between 800 and 3200 for shots like this. I would say to look at your shutter speed settings, and keep it around at least 1/100. So this means that I have exposure for 1/100th of a second. The higher shutter speed means less light can get in...which is not good for night time shots, but since the fireworks are so bright it wasn’t a problem.

Also high shutter speed means less blurriness for shots that involve fast moving objects (like fireworks).

Hope this helps.