Finding Beta Users as an Indie Hacker

Hi everyone!

Hoping to get a bit of advice from the Indie Hacker community!

I've had a couple of projects for a while but as an AI/Coder with limited knowledge in growth/sales => I've built some cool tech, but I need to get obsessively better at Growth/User Testing to make sure I develop products in the right direction.

My (sort of) successful projects have largely been randomised hits (maybe a bit of virality) but it'd be great to hear about how in the early days - if you had the idea first, how you'd go about testing the product for market fit and in particular, how do you find beta users to interview?.