So much of literary sci-fi is about creating worlds that are rich and detailed and make sense at a social level. We`ll create a world for people and then later present a narrative in that world.
Pick up a camera. Shoot something. No matter how small, no matter how cheesy, no matter whether your friends and your sister star in it. Put your name on it as director. Now you`re a director. Everything after that you`re just negotiating your budget and ...
It`ll be all of our efforts together. It won`t won`t ever be exactly the way I imagined it. And that is, I think, an important lesson as well, is that in any group enterprise it`s going to be the sum total of the group.