Backcasting is like playing a game where you start from the end and work your way backwards to figure out what you need to do at the beginning to get to your goal.
For example, let's say you want to be a successful businessman when you grow up. To backcast, you would ask yourself what steps you need to take to achieve that goal. Maybe you need to study hard in school, get a good education, and network with other business professionals. Once you figure out those steps, you can work backwards from being a successful businessman to where you are now and make a plan to achieve your goal.
So, backcasting is kind of like starting at the finish line and making a map to get there, instead of starting at the beginning and hoping you end up where you want to be. It helps you plan your actions with a clear end goal in mind.