Ask HN: Founders, how did you do your market research?

I have a problem I want to solve and I want to turn that into a startup.

Founders, how did you do your market research?

Did you do a comprehensive survey before building your app?

Did you hire a company to do it for you instead?

What do you look for in your market research to validate your ideas? Signals, metrics, etc.

I know I am not the only one having this problem I am eager to solve. Thank you