Biting! help pleasee

[sanzoni]

Hi everyone. I have a 8 month old grey. I know he is still young but he is getting into the habbit of biting hard. If i try to touch him anywhere on his body he tried to chew hard on my finger. Even if he is just perched on my arm he will try to bite my finger, skin, whatever he could find. I don't exactly understand the whole concept of positive reinforcement. When he bites me do I say no? or do I just ignore him. He goes for my fingers so often that I don't have a lot of chances to give him a treat for being good. I just need help because he is a great bird and I want him to stop with the biting. Thank You