I have somehow managed to make a little gizmo that primarily consists of an MCU, some sensors, and wireless connectivity. I have gone through the process of making the initial prototype, then designed a board and made an SMD version. It's small and it works nicely. It also has a nice case that I managed to 3d print then cover in a little homemade silicon sleeve. I made it for myself for fun but it works really well and everyone seems to want one. I could make maybe a few dozen of them by hand and sell them off to the people I run into that want one, but what if I run out quickly? It seems possible enough that I feel a little panicked at the thought, simply because I don't know where to start.

Where do I even begin to figure out how to take something to market? Is there a standard resource library for this sort of thing? I see no other question on the EE SE that asks quite what I'm asking (most people are looking looking for design or product advice, *sigh*, but I've already got that done), so maybe this is completely the wrong forum (another hint: I have no idea what to tag this), in which case I'd be happy to move it somewhere more appropriate.

Other pertinent info: I'm in the USA (NYC area) and possibly could be interested in shipping to other markets (Europe, possibly Asian markets) down the line.

Types of questions I am hoping to find advice for:

How do I find manufacturers for the different components (PCB, getting it soldered together, case, etc.)? Or maybe it's better put to say that I'm trying to find out *how to shop* manufacturers.

Should I split manufacturing to try to prevent IP theft?

Does the shop that assembles the boards also program them?

Certifications???

Marketing and distribution... ??? (I have a decent idea of how to get started here, but resources are always welcome)

Things I'm missing completely?

I feel like I know how to find what I need to engineer something and where to find general business advice, but the chasm between the two seems swampy and mysterious to me.