Be calm and confident.
Be honest towards the profile, you have to know it to do it. So, be hardworking, dedicated and flexible when its needed
There will be 3-4 rounds . Just be confident at the time of interview. The questions will be basic about how will you engage a child, what will you do if the child gets kranky. How will you narrate a story to the class .. some basic ques. like these. Good luck !
The one answer you should give is to tell them I like to work with small children..in doubtly you will get the job here