Perfectly understandable. Especially with the regards to the tie-in business, which is its own weird thing. And trust me, you are not alone. There are lots of misconceptions and confusion about how it works. "How much do you have to pay CBS to be allowed to write Trek novels?"
Speaking broadly:
Regular publishing: It's all about the individual work. You're not applying to work at the company; you're trying to convince them to buy a particular manuscript. So you're not going to show them samples of your previous work or submit any sort of portfolio or resume or photo. You're just going to include a brief cover letter explaining what you're submitting and citing any RELEVANT experience or credits.
"Enclosed is my novel, VAMPIRE MERMAIDS, an historical fantasy set during the Golden Age of Piracy. This is my first novel, but my short fiction has appeared in ASIMOV'S, ANALOG, and STAR TREK EXPLORER magazine. In addition, I'm a professor of Naval History at the University of Maine."
In olden days, it was sometimes sufficient to submit an outline and sample chapters to make a sale, but I'm told that is much harder to do these days, especially if it's a first novel. Publishers are going to want to see a complete manuscript before pulling the trigger.
Or possibly the book is going to be submitted by your agent.
(Note: we're talking traditional, old-school publishing here. I don't pretend to be well-versed in the brave new world of electronic self-publishing, Kickstarters, Patreons, etc.)
Media Tie-ins: You
don't want to write an entire novel before an outline has been approved by the licensor. And how you get the opportunity to submit an outline, or even get a foot in the door, is going to vary from author to author. Chances are, though, you probably already have some publishing experience and credits and connections before you're invited to submit an outline. In general, in my experience, such projects are not usually initiated by the author, but by the editor, who acquires a license, then goes looking around for suitable writers.
"Hi, Greg. We just acquired the ALIAS license. What is your schedule like?"
Mind you, I broke into the tie-in business more than thirty years ago. I have no idea how folks go about it these days.
Hope this makes sense!
EDIT: Oh, I'm told that, nowadays, publishers are possibly going to take your social media presence into account. Do you have many thousands of followers on Instagram or TikTok or whatever? That might make your book seem like a better prospect, commercially.