You learn a lot in a very short space of time when you become a parent. I had never heard of colostrum, fore milk or hind milk until last week.
When a baby is born, the mother produces colostrum, which is full of antibodies to help the baby's immune system. It is thicker and yellower than milk. I didn't take any photos of it but sure enough if you google it and click on images, you'll see that it is the clotted cream of the breast.
For the first few days of life, newborns sleep a lot and the colostrum is enough for their tiny stomachs. After a few days they develop a thirst and if the mother's milk hasn't "come in", the baby will certainly let you know that he is hungry.
Fore milk is thinner, like skimmed milk, and thirst quenching. The baby will gulp it down quickly, with no concern for the inevitable belching that will follow. Then comes the hind milk, which is thicker, like full fat milk and hopefully leaves the baby feeling full and ready for a sleep!