To get started, answer the following questions:
(Do you play for pure combat? You know that other events might decide the nature of that combat, but you just want to blow things up. And think about this: Do you like to micromanage combat, allocating power to personalize your attack/defence strategy, making combat a personal match of wits, or do you just like quick matches that can be over in minutes?)
(You don't care about the combat. You like to write and you want to explore.)
(You appreciate both aspects of game play. You accept that the ship you love to write about may lose battles from time to time.)
(You can stick to the TOS crew configuration of science officer, helm, navigator, communications officer, etc, or you can use the TNG idea of Operations Officer combining some duties.You can also customize your bridge crew configuration. You're the Captain)
Note: unless you have something else in mind, all players in this stage of the game get a Heavy Cruiser to start. The 'something else in mind' I mentioned is if you decide you want a mission-specific ship like a scout or police ship, which is likely to be a frigate or destroyer. Just remember that you might be limiting yourself in a case like that. And don't be intimidated by the need to create a command crew. If you're a story-teller, you're used to this, but it isn't necessary to start. And if you're in it for pure combat, the command crew is recommended but not necessary.
That is really all you need to start. I will happily walk any new players through the first few missions. If you are concerned that you don't have enough time to contribute, don't be. This game is as casual as you want. Exploring takes as much or as little time as you want. Write once a day or once a week. A hundred words or a thousand. The most intense level of this game, heavy combat takes a commitment of no more than one email a day. And even in that case, if you miss a day, it's forgivable. Even the moderator has a RL and the occasional computer issue. The game is turn-based. Combat results will be posted online daily. And if it still doesn't make sense, think of it like your favorite role-playing/writing group gathering for some table-top game playing.