Welcome to the forum!
You have come to the right place! Amazons are known for their "moodiness" and can indeed be nippy.
I am no expert in these gorgeous birds but a few of our members have them and will be glad to help I'm sure. The wonderful Sharon C has the beautiful Freddie and she is so so SO good with him.
The same rules apply to any bird that has been brought home. Lots of patience, talking and respect are needed. Everything is new for your fid (feathered kid) and you must remember this with everything you do. Concentrate on building your relationship with trust and take it very slowly. Stepping up is not the first step...it is actually a few weeks down the line.
Talk out loud, think out loud, read. Spend a lot of time beside the cage but don't try and force physical contact. You can try feeding a treat like a sunflower seed through the bars but don't be surprised if your bird takes a while to respond.
It is a long, slow process to earn your relationship with a bird and forcing situations upon him when he isn't ready to trust you can cause untold damage. Especially with the "uppity" amazon.
I would advise that you get yourself a book. Parrots for dummies is great. A species specific book is beneficial too. These will teach you the basics including how to make sure your bird is fed correctly with pellets, nuts and only a few seeds plus plenty of fruit and veg. No peanuts or dried fruit which contains sulpher dioxide - a poison to a bird. Feeding requirements being mety doesn't only ensure a healthy bird, but you have an increased improvement in temprement.
Books will also teach you how to parrot proof your home, how to avoid deathly accidents via PTFE and lead poisoning as well as many others.
I would suggest that you take your bird to an avian vet too if you haven't already to get a check up to ensure all is tip top. They can also clip your fids nails and wings if you wish.
I'm sorry if you're already aware of a lot of points I have just written already, but I am always so concientious of guests to the forum as well as replying to the OP
Have you decided on a name yet?
Oh and we LOVE pictures so please do post some

!
This will assist any member who can help with sexing too if possible!
Good luck!