You have just got this grey so you need to give him time to settle in and feel comfortable in his new home, you seem to not know much about the african grey so why don't you read all you can especially the threads here so you will know what to expect but I get the impression you only wanted a bird that talks, well he probably has a wide vocabulary but you won't hear it until he feels more relaxed in his new home.
You cannot make a grey stop biting or say the things you want him to say, only time and lots of patience will accomplish that along with the proper care to develop a bond between you and that my friend has to be earned so get busy and read thru all the threads and then you will have some idea of what you are facing.