You're solving a problem for people so start by thinking about what kind of person has this problem - are they in a specific job or industry, are there subreddi

You're solving a problem for people so start by thinking about what kind of person has this problem - are they in a specific job or industry, are there subreddits that overlap those people, maybe you can use facebook and google ads to hook them, or twitter to reach them directly. Maybe you know some of them personally. A small number of your ideal users can make great beta testers and then customers.