How do I pitch a start up idea?

I have never started a business or built anything. I have an idea which I believe will work well. Where do I find contact details of people with whom I can share this idea with.

I mention them as people because I don’t even know who to contact. Watch a bit of shark tank, for some reason my brain keeps bringing peyush’s face. I am newbie. Any help would be appreciated.

The idea is of an app. We’ll provide a service of connecting two parties.