To monetize your app made in AppsGeyser (to get revenue from ad impressions while the application is used), it must necessarily be published on the Google Play Store.
How to do this is described in the step-by-step instructions in your AppsGeyser Dashboard Remember: it's just a guide, your app will not be published while clicking this steps, but you will learn how to publish your app by yourself!
Also in this video, you will find a detailed guide to registering the Google Play Developer account and publishing the app on the Google Play Store.
To activate monetization in the app after it was published on Google Play, you need to fill the required forms on the Monetize tab in your AppsGeyser Dashboard. Detailed instructions for setting up the ads in your app: AdMob and MoPub.