Welcome to the forum. Your new birds behavior sounds within the normal range of behavior for such a young bird in a new home. Smaller amazons too are known for being a bit more timid and shy than their larger cousins. It sounds like he is a parent raised bird, which means the parent birds were allowed to care for him with little human contact until he weaned VS being pulled from the nest and being hand raised by humans)? Typically with parent raised birds, they do not just "come" trusting and being interested in humans like hand fed babies. This does NOT mean they are not 'good' birds nor does it mean they have no potential to be good companions! He is probably just very frightened of his new surroundings and family because he has likely not had very much interaction with humans and probably not made many positive associations with humans yet.
First thing, the general recommendation with timid new parrots is to pull up a chair close to their cage and just talk to them in a soothing, calm voice (all members of the family/household do this so he makes positive associations with everyone he'll be living with), which it sounds like you're already doing or trying to do. Do it several times a day for as long as it takes. Once he starts acting a little less frightened, start bringing some food over with you (good way to introduce additional fruits and vegetables, as parrots need a varied diet). Eat the food, and no doubt within a couple days he will start being interested in what your eating. Reward him when he comes closer by offering him some of the food and praise him when he takes it from your hands. The goal with a new bird is to get them comfortable with you from the safety of their cage, THEN move on to working with them so they can start interacting with you and come out of the cage. It can take several weeks for a new bird to start feeling comfortable with you. Have patience and let him come around on his own time scale. He will (they always do with enough patience on our part)
Next, I see you are in Saudi Arabia. I am not sure what all is available over there for parrots, but it is strongly recommended amazons be fed a pelleted diet with lots of fruit and veggies. Seeds are very high in fat and low in nutrition for parrots and a seed diet will drastically reduce his lifespan. If pelleted diets are not readily available, he would need to be transitioned to a fresh foods diet of grains and beans with ample fresh produce. Either way, he needs to be transitioned off seed and onto something more suitable and nutritious. The diet section on this forum has a lot of fantastic advice on how to switch a parrot to a healthier diet gradually and wean them off seed. Also lots of advice on bird safe fruit and veg, so whatever is safe to feed and available locally should be offered and encouraged for him to eat. A proper diet helps a lot in improved temperament, especially with amazons as they get older.
What kind of setup do you have? I know cage size recommendations vary in different parts of the world, but he should have a sizable cage with lots of room to move around. He should also have a variety of perches in different widths, preferably natural or made of rope. Those straight perches frequently included with cages can be quite uncomfortable for them. He will also need toys, which will keep him active and mentally stimulated. If he already has toys and is not interested, it is ok and not uncommon for young and untrained/unsocialized birds to not know what to do with toys and that can be addressed once you start building some trust with him. If he does not have any toys, I suggest providing some as soon as possible. Last, do you have some photos of him, how he's been sitting etc... It would be helpful to see him, especially his eyes if possible. It is not likely but entirely possible this is a much younger bird than you were told and he is not fully weaned, which would lead to not perching properly and not eating much solid foods. Eye color in baby amazons changes as they get a bit older so it would be helpful for us to see him to see if he actually looks to be a year old or potentially younger. If that were the case, there would be some additional steps for you to take.
Edit: As Anasai said, if you can, taking him to see an avian vet would be ideal to be able to see what an expert who can physically examine the bird has to say.