Talk to a trainer. He will explain their hours of operation, fees and methods of training. You can also find out his experience as a boxing coach and whether he was a fighter himself at one point. Meet the staff and get a feel for the place. If it fills you with a sense of excitement and anticipation, it's probably right for you.
Do ask questions. Find out what they would recommend for you and what kind of training you should start. What's their schedule like? Who would you work with? How can you meet everyone? Make sure you know what you're getting into before you sign up.