How to take an idea from concept to reality?

First off, I am not entirely sure if this is the right subforum for my inquiry. If the moderators feel this topic belongs elsewhere, please feel free to move it.

To get straight to the point: I have an idea for a service—potentially a website or a mobile app—but how does one actually transition from a mere concept to a finished product?
The situation is that while the conceptual framework is fully formed, I lack the technical expertise to program it myself.
Where should my first step be? Should I be searching for a business partner, or simply looking for someone to build it on my behalf? Furthermore, how can I protect my intellectual property? My fear is presenting the full concept to someone only to have them bypass me and pursue the project independently. How can I prevent such an outcome? Is a patent the appropriate route here? Can an idea even be patented? Additionally, would I need to register a legal business entity immediately?
The target market could potentially be global, though I am also considering a more specialized local niche.
Is there a specific institution or agency in the US that provides guidance on these matters?
I have attempted to research this via Google, but I have yet to find any information that truly addresses my concerns.

This belongs in the right subforum.
I don't know what you're thinking—but you're gonna burn through a massive amount of capital just to get this off the ground. Hopefully there’s some actual data backing this up... unless you've already proven it isn't a total waste of money?