You can participate in discussions like this: https://news.ycombinator.com/item?id=44416093

Have you offered them money?

You don't, they do. You go to GitHub or a hackathon and start building in open, you frequently talk about your project and make it useful for someone other than yourself. You make sure that you highlight your interest to partner up with someone and provide a way to start the discussion with you. If you do this long enough, many will contribute to fix their own issue, and some of them may contribute more than that if they find the contribution to your project aligns with their current goals (career, reputation, learning, etc.).

I think this is very cool, and I support your work, however everyone has multiple open source concepts they're working on at any one time. You need to either build the product yourself until it has market traction, or you need to pay people. Very few people, other than your friends, will jump into a project for no money or equity.