How to set up auditions?

I'm a 13 year old girl trying to put together a web series. It's not easy. So, I've cast all the girls, but I just can't seem to cast any boys. I've been thinking of a school-wide or city-wide auditions. I live in a relatively small town in Florida so that won't be too difficult. I already have a venue in mind, so how do I set up these auditions and make sure they go off without a hitch?