I have an idea for a software I believe is new, but don’t know where to start?
Oscar, I'm assuming on the programmer side, or at least have some level of coding experience. Regardless though, I'd recommend you start out by visualizing the full breadth of your idea if you haven't already. There are tons of templates for doing this, but try using the Lean Canvas, which guest contributor Maarten Ectors wrote a great article about. That's going to help you organize your thoughts into something resembling a pitch, and if you have trouble filling out all the sections of that template then the chances are your idea hasn't reached full maturity yet.
If you can fill out the entire sheet however, it's probably worth seeking out some trusted friends and/or contacts (people who won't ripoff your idea) in the enterprise software industry and shooting your idea by them to see whether it's been done or if would fit into the present market.