You really need to get the book Hand-feeding and Nursery Management by Howard Voren and Rick Jorden. Its like the bible of feeding day one chicks. I can't recommend it enough. Order it tonight if you can find it. Hopefully its still in print. The only thing outdated about it is the hand-feeding formulas although frankly I think the old time formulas put weight on day ones better than manufactured formulas. After the first week or so you can switch to the manufactured. For now, you probably just have Kaytee or Zupreem to work with which is fine. The growth curve of the chicks will just be a little different and you'll need to do the round the clock feedings. Manufactured formulas produce prettier feathers. Hand-made formulas come with a host of pitfalls but if done right can get the chick gaining weight at pretty close to the same rate as a parent fed chick and let you sleep longer. You can feed it thicker and maintain hydration. Probably not something you want to mess with for this clutch, but possibly look into if your are stuck hand-feeding another batch from day one. There are other little tricks you can do to help move things along too and get better weight gains. Amazons have slower metabolisms than other species, so just the regular manufactured formula might work just fine. I've only ever done quakers and as of right now a parrotlet from day one and they have problems with hydration. Which makes it hard to feed formula thick enough to get good growth. without getting dehydrated. Bigger babies still have issues with it, but not as bad sometimes.
Anyway, to answer your question for today, people differ on the specifics. For sure you want to wait until the chick is dry and produces its first poop. Many people wait a full 12 hours or a little more before starting to feed with formula just to make sure the yolk has a chance to start digesting. If you see really obvious yellow or greenish yellow under the skin of the belly around the umbilical scab, then its probably best just feed fluids and wait toward the longer side of 16 hours or so before starting formula.
My first feed is usually just fluids. I get a bottle of Pedialyte from the grocery store and mix it half and half with water. For the first few feedings, when in doubt, go light on the size of the meals until you get an idea of how the crop works. There are better electrolyte solutions out there for baby birds, however, I've always just used Pedialyte. But I don't use it past the first couple days and I don't use it full strength. Have you ever fed a day one of some other species?
Also, keep the humidity up in the brooder. Depending on the structure of your incubator, you can leave the chick in the incubator for the first day or so where its really humid for the other hatching eggs. So long as the baby can't stretch out its neck and get into trouble with mechanical incubator parts. But after that, they really should be kept a good .5 degree or a full degree lower than the eggs. So when you move to the brooder, remember to have a bowl of humidity in there. It helps the chick stay hydrated and actually allows you to start feeding formula a little thicker sooner. But not until the first couple days have passed if you are using manufactured formula. I always elevate my humidity bowl a little bit so there is zero chance of a chick crawling out of its container and into the bowl. They can be surprising mobile sometimes using bedding as a ramp and end up where they aren't supposed to be. I keep day one chicks in somewhat high sided square bowls and make a little nest out of soft toilet paper. Then just change the TP at every feeding.