EllieMae, there is a show in Columbus May 4; that's the last one in Indiana until September. The best way to learn is just to do it; you'll find that other exhibitors are great at answering questions and giving advice. The Marans aren't difficult to get ready to show--a bath and nail trims a couple of days before, last minute touch-ups the morning of the show--wiping off the poop that they've invariably waded through, vaseline or oil on beaks, feet, legs, comb, etc., and a mist of pink shine spray. Oh, and be sure that they are the French variety with the leg feathering.
You don't have to have any blood testing done unless you show out of state.
Go for it--more people need to see this great breed. They haven't caught on as quickly around here as in some other areas.