From this article, I can see what backstory does (or should do), but not what backstory actually is, other than that it’s longer than a flashback. How much longer? Days? Weeks? Pages? Chapters? I’m of the simple understanding that while a flashback is a temporary shift in the story from the present to a particular scene from the character’s past, backstory is essentially all the “stuff” that has happened to the character (or to a place) before the actual story begins. The backstory is initially unknown to the reader, but is revealed, piece by piece, throughout the main story to add depth or to provide clues to the story’s outcome.
Somehow back at home, support for the soldiers meant having a five-year-old kindergartener scribble a picture with crayons and send it overseas, or slapping stickers on cars, or lobbying Congress for an extra pad in a helmet. It’s interesting that a soldier on his third or fourth tour should care about a drawing from a five-year-old; or a faded sticker on a car as his friends die around him; or an extra pad in a helmet, as if it will protect him when an IED throws his vehicle 50 feet into the air as his body comes apart and his skin melts to the seat.