All businesses start with an idea - almost a story idea since it's "What if...?"
"What if I wrote scripts, people turned them into productions and people saw them?"
That's where your business model starts: with you and your idea. It is the fundamental, the thing that drives everything else. All to often someone starts a business producing one thing and life happens, it changes, they bring on other people who modify the basic idea. And suddenly you're working in a business that you didn't want and not enjoying it.
It happened to me. And for 4 years I was miserable trying to convince myself it was the right thing. But it wasn't.
So that basic idea needs to stay pure. This is your goal (or goals), something like "Writing highly successful scripts that are in demand". You can review your goals from time to time but that should be from the viewpoint of "how am I doing" and "is there some way I can write this goal better?" rather than changing anything.
All businesses have legal stuff they have to deal with, and it's important that this is separated out from the rest of the business. Otherwise you get distracted. As a silly example: The cleaner has business contracts dumped in his lap to approve.
Of course if you're on your own it's harder to separate these things out, but you need to. It doesn't mean your ignore final demands from the electric company, it does mean that you allocate time to deal with these things and when it's done you put it aside.
If you're lucky enough to have an agent then the contract side of things fits in this section.
Finally you have Planning and Management: What you need to plan is up to you, but it should be a set of steps that will lead you to your goal. These steps need to realistic, they might involve getting training, the bigger plans could span years, but the key point is this: do they lead to your goal(s)? The management bit is organising things so that you can achieve the steps and ultimately achieve your goal. Reading, or seeing in person, Adrian Mead would certainly help you see what your plans ought to be.
Things you could do:
Write down your overall goals, the big ones. Don't be afraid of big goals. Better to shoot for the stars. Look through your current life, are there any legal things that could do with handling? Write those down in a list, see which one you could deal with first (probably the most pressing) and deal with it. Now that you've got your goals have a go at breaking them down into smaller steps, different stages, and then break them down further into smaller steps. Get Adrian Mead's monograph "Making it as a Screenwriter" for other excellent advice.
Next time we'll look at some basic organisational bits.
What's on the turntable? "Barrytown" by Steely Dan from "Android Warehouse"