How do you even get user interviews?

Hey, I am a new PM with 2 yoe as a full stack dev. I was looking for a change so I got a job at a start up. The team is small and I am expected to do everything from validating a product, sales, meetings with senior engineers to design the product etc.. We are building a software for accountants and I don't know anything more than what the internet offers on what an accountant does so instinctively I have decided to outreach to a few people on linkedIn a