How to query in firebase using MVP android

I'm learning MVP design pattern and I have retrieved data from the firebase realtime database in RecyclerView. Now I want to Query Data, how can I do that? I have searched a lot but didn't find any relevant solution to my problem. This is my code which I'm using to simply show data in recyclerview using MVP design pattern

Interface :

public interface DashboardContract {

    interface View {

        void onEventRead(ArrayList<Events> allEvents);
    }

    interface Presenter {
        void retrieveEvents(DatabaseReference databaseReference);
    }

    interface Interactor {
        void performRetrieveEvent(DatabaseReference databaseReference);
    }
    interface onOperationListener{

        void onRead(ArrayList<Events> allEvents);
    }

Interactor :

  @Override
    public void performRetrieveEvent(DatabaseReference databaseReference) {
        databaseReference.addChildEventListener(new ChildEventListener() {
            @Override
            public void onChildAdded(@NonNull DataSnapshot dataSnapshot, @Nullable String s) {
                Events events = dataSnapshot.getValue(Events.class);
                allEvents.add(events);
                mListener.onRead(allEvents);
            }

Presenter

private DashboardContract.View mView; private DashboardInteractor interactor;

public DashboardPresenter(DashboardContract.View mView) {
    this.mView = mView;
   interactor =  new DashboardInteractor(this);
}

@Override
public void retrieveEvents(DatabaseReference databaseReference) {
    interactor.performRetrieveEvent(databaseReference);
}

@Override
public void onRead(ArrayList<Events> allEvents) {
    mView.onEventRead(allEvents);
}

Activity

  DatabaseReference  databaseReference = FirebaseDatabase.getInstance().getReference().child("Head").child("Events");
    DashboardPresenter  mPresenter = new DashboardPresenter(this);
            mPresenter.retrieveEvents(databaseReference);
     @Override
        public void onEventRead(ArrayList<Events> allEvents) {
            this.mEvents = allEvents;
            dashboardAdapter = new DashboardAdapter(DashboardActivity.this, allEvents);
            recyclerView.setAdapter(dashboardAdapter);

        }

This is my firebase database snapshot :

Note:

1. I want to Query data using charges entity.
2. How can I do that, where should I query it?