Dawn, I am so glad you are finally in a place that can rightfully be called a school.
Your colleagues (finally, you have colleagues!) are right about the misbehaviors you have already experienced. Deal with it immediately (and without emotion). Speak matter-of-factly to the kid and be specific in describing the behavior(s) you expect. Kids are amazingly compliant when they know how you want them to act!
Talk to your colleagues often. I think they will be a good source of information for learning and growing professionally.