Sin and Satan are the same thing: bad decisions that lead to a bad future. You could say sin is the bad decision and Satan is the future result of the bad decision. A bad future is a future that doesn't exist, because the future must be good to exist at all. Think about natural selection, for example. Only the fittest shall survive. And since we know there is a future, it must be good!
That may be the original idea of sin: to give people a way to remember that only good decisions survive after death. The idea has evolved through the generations and experiences over the millennia. Today, we think there's some powerful bad guy named Satan and there are places called heaven and hell where you spend eternity when you die, depending on whether you were a sinner or not (spoiler: we're all sinners).
The original idea seems much simpler and practical: make bad decisions, and they will not survive your death and will not contribute to the future paradise. Make good decisions, and those will survive your death and you will have contributed to the future paradise: Heaven!
Moral of today's story: Make good decisions for goodness sake! Because otherwise, you are just throwing away the opportunity of a lifetime: help build the future paradise for your descendants!