Asides from that, where submitting novels is concerned, it seems like a very secretive and overly complicated process that not many people are willing to explain.
Not at all. Several people in this thread have already explained it. And it's not that different from getting a job in any other profession -- namely, first you have to go through the audition/interview process and prove you have what it takes. And in order to have what it takes, you have to get enough hard work and experience under your belt to develop the skill. It only seems "overly complicated" if you start off with the totally false assumption that you can go from interested amateur to successful novelist overnight. It takes most writers
years of writing, submitting, being rejected, and learning from the rejections to develop a high enough skill level to be competitive with all the other experienced professionals who are competing for a limited number of slots. That's why it's not easy -- not because there's some secret conspiracy to exclude people from getting in the door, but because, as with any other professional discipline, you have to
compete to get in the door and you have to
earn that access through talent, discipline, and hard work.
So how does an unpublished author get their foot in the door, where Star Trek is concerned?
They probably don't, for the same reason someone with no professional architectural experience is unlikely to be hired to design a skyscraper. This isn't a hobby for amateurs. This isn't fanfiction. It's a professional discipline and you're competing with experienced, professional authors. Like
Therin said, the best way to have a shot at becoming a
Star Trek writer is simply to become a writer, period -- to write your own original fiction, submit it, get it rejected, learn from the rejections, repeat several dozen times until you finally get good enough to sell something, then repeat more and more until you sell enough to get a reputation or an agent, and then you can give it a try.