Guppies have a really simple lifecycle.
Guppy fry are free swimming right from the start. Once they are born, the first thing they do is to look for a place to hide.
Guppy fry are small. Most of the time adult guppies and bigger fish will eat them. To save your fry, you might want to separate the pregnant guppy female from the rest of the fish, or provide enough hiding spaces, such as live plants, to your fry.
Guppy fry will eat the same food as their parents. However when you feed flake foods to them, make sure you crush it up into powder. Frequent water changes are a must, especially if you feed your fry multiple times a day. guppy breeders do complete water changes every day or every other day.