hi
not too worry i'm also new to the African grey world but have learned this:
if its bad for you then its bad for the parrot!
ie no coffee, chocolate, alcohol, fried foods ie chips or crisps. my bird vet tells me that sunflower seeds are not part of her normal diet so don't feed her yet others do, I've chosen not too.
she needs fresh fruit and veggies daily with a maintenance pellet to eat and fresh water each day.
i do this morning and evening so as to ensure that there is no bad food around her.
regarding quantity i give her small handful each morning and evening of the fresh food and fill her bowl with the maintenance pellet.
due to the heat in my country, food goes off quickly so i chop up loads of carrots, broccoli, spinach, cabbage into small pieces which then get refrigerated and i give her a small handful each morning and evening. she likes corn as well.
she then gets freshly sliced apples, or whatever fruit is available except avocado. shes doesn't seem to like pears but i don't spoil her too much with choices.
also a little boiled chicken she likes too, pasta without any sauces.
shes sometimes eats from my plate but because i enjoy spicy food, don't let her get too much
hoping all this helps