How did you get your first paying customers?

Hey folks, I'm Abdelhakim Ouafi and I've launched my first business in product hunt today and I want to ask people how did they get their first paying customers? which channels did u use? Tructivity is a web application which is a school planner for students it can be installed as a desktop application and soon I will launch the app in Google Play & app store. https://www.producthunt.com/posts/tructivity