Run Button is Disabled in Android Studio

I can't click the run button. Does anyone know how to fix it?

Click Run on the menu and then Edit Configurations... then click on Android Application on the left and click the + button. Choose Android Application from the pop-up menu. Then pick the module (its normally app or something like that). Then click apply and ok.

If you have more errors after that, try to re-import the project in Android Studio.

When creating the Run Configuration, the dropdown for Module had only <no module> for me. Invoking menu File -> Sync Project with Gradle Files added app to the dropdown for Module. Then the Run button became enabled.