Don't put your hand in his cage, he WILL bite you as you found out. That is HIS territory, do not invade it while he is in there. You should open the door, stand back, and let him venture out on his own when he wants. You could be in the same room, gently, sweetly talking o him. He is in a new place, new people, different surroundings, scary stuff for a bird.
His world as he knew it is gone and that's frightening, he doesn't know you or that you are his new home. That will require lots of understanding, comforting woods, and reassurance. talk to him all thectime when your around with a calmness and gentleness. Tell him what you are doing. When he does come out, give lots of praise, "good bird, etc.". As he learns, you are not a threat, he will most likely step up for you when he is ready and then you can slowly, but gently put him in his cage when you need to. Make sure you move slowly around him, offer him a treat that you are holding in the other hand as you get hiim to step up and put him in his cage for distraction.