The Egyptians started farming a little later than their neighbors in West Asia and about the same time as other people around the world, probably around 10,000 BC, but definitely by 5200 BC. At first people farmed by just digging a hole in the ground for each seed with a stick, as you do when you plant a vegetable garden in your backyard.
But that’s hard work, and slow. It is particularly hard in Egypt, because the heavy, clayey soil laid down by the Nile floods is hard to make furrows in. So by around 3000 BC people in Egypt had invented the animal-drawn plow, which made planting a lot easier. Here you can see a man plowing a furrow with an ox while a woman scatters the seeds behind him. Egyptians also farmed with donkeys, which they got originally from Sudan.
When the grain was ripe, in March (for barley) and April (for wheat), Egyptian men and women went out into the fields to cut the long stalks. Usually men cut the grain with a sickle, while women picked up the cut grain and tied it into bundles. The seeds of the wheat or barley were ground up to make flour for bread, or brewed into beer, while the stalks were useful as straw for making everything from sleeping mats to shoes and roofs.
Ancient Agriculture: From Foraging to Farming, by Michael and Mary Woods (2000). For middle schoolers, with plenty of information about how farming got started, and how it worked.
Farming & Food (The Ancient Egyptians), by Jane Shuter (1998). Easy reading.
Everyday Life in Ancient Egypt, by Lionel Casson (revised edition 2001). Not especially for kids, but pretty entertaining reading, and Casson knows what he’s talking about