Eventually, we're planning on a fully coded GM system that will allow players to run adventures with specific tools designed to support with clearly defined coded permissions and restrictions, such as the ability to spawn NPCs, code item rewards, access and reveal metaplot secrets and add them to sheets, and allow player feedback about the GMs that will help determine their restrictions. In the meantime, for alpha and beta, it's much less formal and there won't be coded support yet for anyone wanting to tell a few stories. We're delighted by anyone that wants to do this, and we do want to support it, but there's a few tricky caveats.
1: We won't be giving out special staff bits, coded support, items, and so on in the interim. Mostly we just don't want to duplicate work until we get the real coded system in, so anyone running stories will be winging it with @checks and @emits. Feel free to use tchotchkes from shops to make custom little things for plot items.
2: Just check with Apostate if a story works thematically. I really am not that big a stickler on stories and would be happy to bat around ideas to see what might work, but there's a whole lot of hidden theme and plot elements that would be surprisingly easy to contradict, and we want to keep the story very coherent.
3: The game isn't designed as a sandbox. This is the real tricky one, and it's pretty core to the game design and I apologize if it's a turn off for anyone wanting to story tell. I don't really want things to exist only in isolation that could disrupt the continuity of anything else. For example, if something is run in a public room it must be possible for any character that could organically wander in to be able to do so. It is entirely okay to run things only in private if that would be too disruptive, but if something is in public, it must be publicly accessible in a way that is logically coherent with the state of the rest of the game (no alternate chronologies, for example). Similarly, if something happens, it has to be able to be pursued by other characters in the rest of the game- I'm okay with dealing with a million investigation jobs about why part of the city blows up, but players and storytellers have to be aware that nothing is intrinsically limited in scope and consequences could easily surprass what a storyteller intended. If something even unwittingly could have ramifications for the rest of the game, we have to be able to run with it due to wanting to make sure there's never any drift into separate sandboxes and split continuity.
So tl;dr- just ask Apostate, be okay with randoms joining in if you run something in public, and stories could easily spawn other stories.