How to connect java android app from Android Studio to App Platform?

Hi!

I’m on the App platform, and I try to “Create resource from source code”, and I choose my repository on GitHub, but I get a “no component detected” error.

So I looked around and found this answer saying that you should add a dockerfile. (Here:https://www.digitalocean.com/community/questions/what-are-the-possible-options-for-deploying-my-java-application-to-digitalocean)

I’m doing this for the first time. I don’t know what should go on the dockerfile or where the dockerfile should go! My app is in java, and I’m writing it on Android Studio and storing the code on GitHub.

What should the dockerfile contain? Where should I place it?

Thank you so much for any help :)