When a production house releases a film, they usually have big promotions plans lined up. They'll pick a day to launch their movie, have critics and influencers preview it, and run a ton of ads to hype it up. You can do something similar for your podcast if you have access to influencers, an existing audience, or money to promote your show. You can follow the same script. You'll pick a date a few weeks away, start reaching out to people you think might be interested in the show, try to get your podcast reviewed, and run a lot of ads to your podcast when it launches.