Really all you need to do is show up and there will be plenty of people that will assist you.

At first I wouldn' t worry too much about rules because most likely you will be there for fun and practice.You just pay your money and tell them you are shooting for fun and shoot what and where you are comfortable.Don' t worry too much about score and have a good time.After a while you may want to start competing for real and then the rules need to be followed.Just make sure they know and there will be no problems.