Ask HN: I am creating a project on opensource,how to gather people to contribute

I am working on a project involving transferring of sound from android to some port of PC, and a python library at the backend can get the voice and use it in other applications, with the enthusiasm of OS I want to gather more people around and want to collaborate, how this is possible. I have seen big repos like Python-Requests, Beautiful Soup etc there are many of the contributors they contribute to a cause, how can I make my repo like this.