How do I debug React Native native module in android studio?

Question

Looking for an answer I came across this post: https://stackoverflow.com/a/38007808
However I don't know how to...

launch the React Native packager beforehand

as Jean Regisser suggest to do before in order to start debugging.

This is what I tried so far:

Nothing works. Help!

user_456588 · Answer

First of all, you should open the android bin(which you have in your react native project) with android studio. And run "npm start" in your project.

user_5744858 · Answer

Finally I found a way:

And that's it!

See: https://developer.android.com/studio/debug/index.html#attach-debugger to know which button I meant.