Let's start with a bunch of people living by the bank of a muddy river. One of them invents the plow, it not even a good plow, just a sharpened stick towed between a couple oxen, but it helped them grow enough food to support craftsmen. Then someone got the idea to irrigate the land from the river, more food, more craftsmen. As the grain supply increased, storage became necessary. Clay from the river in the hands of potters solved that. Knowing whose was whose led to writing. Digging those ditches, and doing it well, developed the skills for engineering and mathematics and these led to architecture. Watching the river for floods showed them that it flooded regularly (spring) and that certain stars always rose just before they did. The large scale organization they needed for regulating the farmers planting became government and laws and a police force. Protecting the grains (and other wealth) from invaders who would take it required an army and an army required weapons.
And so Egypt became an Empire.
No, no, no - see, you start out with crude huts and wells and dirt roads. Then you learn how to hunt ostriches. So you build granaries and bazaars to feed your people, but then they get whiny and want to be entertained. And the gods want to be worshipped or they send plagues and destroy buildings. It's some time later that you finally learn how to farm on the flood plains... haven't you played the campaign through?
What? You mean reality isn't like the game Pharaoh? How about Children of the Nile?