If you dont have any previous history on your grey it is hard to know if he had any basic training or if he has been socialized well.The most important command a grey owner can teach their grey is the step up,i have included a link for you...Keep training session short no more than 10/15 minutes perhaps three times a day if you can.Always reward positive behaviour,even the smallest of achievments,never tell your grey off or react to bad behaviour..
http://exoticpets.about.com/od/behavior/f/birdstepup.htm
As for biting, as hard as it may be never show any reaction this is just what your grey is looking for.If your grey is on you,which i know he doesnt step up at present,you can slightly wobble your hand & this throws them off balance,always follow up with a firm No.If he is on a playstand or perch etc.. A firm no & walk away from him for a few minutes,in time he will see that bad behaviour brings him no rewards.