I don't think there's a "set in stone" method of unpacking your new cham but,,, what I do is take the container, put it in the cage and let him/her get out on their own will. I'm sure the transit was weird enough for them and having a stranger handle them would just add more stress. As far as misting and feeding goes, you could pre-mist the cage prior to releasing it to reduce direct interaction and help it acclimate better. I'd wait a few hours before offering anything to eat. That's what I do, but others will probably have other ways of doing it. Bottom line is just to induce the least amount of stress to your cham.