Hello Stacey and welcome to the family, so glad you have decided to join us and we look forward to hearing more about you and this new grey.
Yes a young grey can be a little clumsy, after all they are a heavy bodied bird but they usually get over it real soon but I don't quite know what you mean by he is very clumsy, maybe he should be checked out by an avian vet, certainly part of the coming home process.
When you say nippiness I imagine you are talking about mouthing you and not actually biting, greys use their beaks like we would use one of our hands, to check out things and as long as it remains just mouthing then don't sweat it but if it becomes bites then you will have to tell him no bite and turn your back on him for a bit thyen try again.
For lots of useful information read thru the many threads and do not hesitate to ask any and all questions you may have and we will do our best to find you some answers and help you in any way we can.
When you get the chance to get some pictures of Frank please share some with us as we would love to see him.