OTOH (since you can't set em of on the 4th anywhere but the US... and even there it's not gonna look like a firework)
I've looked at the ones in my boat. The one's in the "gun" are pretty obvious - point away and pull the trigger. One could say that if somebody didn't figure this out it's evolution in action.
The hand held ones are pretty obvious to me too (I've got a few on board too). Point away and pop the cap - like the instructions say.
For "practice" I'd be more prone to excersize my pyro tendencies. i.e. I got to set crap off legally.
? Read the instructions. Don't do stupid.