It’s an opportunity to learn more about the program and connect. I’d think of it as a 2 way street – they school wants you to know about their program, and this is a chance to “sell” you.
But it’s also a chance for you to show your interest and sell them on you.
I’d thank them for reaching out and ask some questions – i.e., who is eligible to audition (do you have to have taken a class), can you try out for every show, when are rehearsals, etc.
Remember that sometimes, your interest may be noted through your application and/or the teacher who is reaching out was really busy (with a show?!) earlier.
In any case, use this opportunity!