After you initialize the AppLovin SDK with your SDK key in your app, an automated process adds your app (by com name) to the dashboard.
Even if you are seeing ads, this process might take 40–60 minutes depending on the backlog of apps we have yet to add. If you are a publisher with dozens or hundreds of apps, you can also search for the com name of the app explicitly by selecting AppDiscovery > Monetization > Manage > Applications and then using Control-F to find the com name you initialized.
Another common explanation is that the SDK key you are using is incorrect. Please ensure that the SDK key has no leading or trailing spaces or additional characters.