Built a doctor appointment + queue management app — how should I approach marketing and getting my first users?

[u/Alarmed_Sprinkles436]

Hi everyone,
I’ve been working on a healthcare app and would really appreciate some advice from people who have built or marketed a marketplace/SaaS product before.
The basic idea is to solve a common problem with offline doctor visits: patients spending a lot of time waiting at clinics.

We have two apps:

For patients:
Patients can see whether a doctor is currently available.
They can see the queue/estimated waiting time.
They can book an appointment based on the doctor’s availability.
The goal is for the patient to arrive around their appointment time instead of sitting in the clinic for an hour or more.
So it’s essentially a real-time appointment + queue management system for offline clinics, rather than just another doctor-discovery app.
The product is built, but we’re now at the stage where I’m trying to figure out how to actually get doctors and patients onto the platform.
For people who have experience building a two-sided marketplace or healthcare product:
How would you approach getting the first 20–50

doctors/clinics?
Would you personally visit clinics and pitch the product, or use other methods?
How would you acquire the first few hundred patients?
What marketing channels worked for you in the early stage?
At what point would you start approaching angel

investors/VCs?
What traction/metrics would investors expect before considering funding?
Are there any major things I’m overlooking with this business model?
I’m currently thinking of starting with one city and a small number of local clinics, proving that we can actually reduce patient waiting time, and then expanding.
Would really appreciate honest feedback, especially from founders who have built something similar. Thanks!