I'm sure you've gotten lots of great information from other users already, but I can go into the behavior. I have owned two chameleons now, and I manage the pet center of the pet store I work at. Chameleons are NOT social creatures for the most part. They usually do not like to be kept together, and they most often avoid interactions with humans. Now, obviously, this isn't all encompassing, but in general this is the case. I had a veiled for a year before I had to give it to a good home because I moved and didn't want to stress him, but he would hiss and snap at me even while I was just misting the tank. However, my newest friend Merlin, a jackson, loves to hang out with me, and my shoulder and my head are some of his favorite places to be. He was fairly shy at first though, and for perhaps the first week he avoided my hand like the plague. Now I can't even mist the tank without him crawling out and coming to a rest on my shoulder.
Remember that each chameleon has a unique personality, and it's important not to overstep his boundaries as it will cause undue stress. Reach your hand in and offer it to it as a perch, always approaching from the front at eye level; if it hisses or backs away, simply take your hand away. Chameleons don't have the mental capacity to form opinions about individual humans, however they can attach you to positive experiences such as feeding and watering. Just give it time, it may warm up to you eventually. Remember though, chameleons are more often than not more of a look don't touch animal.
Hope you have a great adventure with your new friend, and I wish you the best of luck

There really aren't any reptiles quite like them out there, trust me, I've had most of them

This forum is the right place to be, I can't begin to tell you how helpful and knowledgeable everyone here is.