Respectfully, it is unusual for a startup to have no connections to draw upon talent. I'll take your statement at face value. The first place to start is by clearly defining the experiences you want someone to have and what you want them to accomplish. Don't do a long tail list of skills. You won't find them. The only definition of fit you want to consider is whether the person will work the hours you need them to work. You are kidding yourself if you think you know how to assess for anything else.

Next, reach out to people you know and start talking with them about their work and who they know. Then contact those people about the role, see if they are interested and who they know.

Or you can hire a recruiter (someone like me) and pay me to do this work for you, pre-screen them based upon your criteria and make the process easier.

BTW, you can watch some of my No B. S. Hiring Advice videos on YouTube and learn more of the things you don't know. My channel is TheBigGameHubterTV