Saving activity when rotating the screen

Question

I have three buttons in the application and 3 textview with a counter. When you press the tv button, it records the number in ascending order, depending on the number of clicks. And when you turn the device, everything is reset and the activity is recreated. Please help, I do not understand how to save the current activity information?

import android.os.Bundle;
import android.view.View;
import android.widget.Button;

import com.arellomobile.mvp.MvpAppCompatActivity;
import com.arellomobile.mvp.presenter.InjectPresenter;

import com.geekbrains.lesson1.R;

public class MoxyMainActivity extends MvpAppCompatActivity
        implements MoxyExampleView, View.OnClickListener {

    @InjectPresenter
    Presenter presenter;

    private Button btnCounter1;
    private Button btnCounter2;
    private Button btnCounter3;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        btnCounter1 = (Button) findViewById(R.id.btnCounter1);
        btnCounter2 = (Button) findViewById(R.id.btnCounter2);
        btnCounter3 = (Button) findViewById(R.id.btnCounter3);
        btnCounter1.setOnClickListener(this);
        btnCounter2.setOnClickListener(this);
        btnCounter3.setOnClickListener(this);

    }

    @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putString("key", "value");
    }

    @Override
    protected void onRestoreInstanceState(Bundle savedInstanceState) {
        super.onRestoreInstanceState(savedInstanceState);

    }

    @Override
    public void onClick(View v) {
        presenter.buttonClick(v.getId());
    }

    @Override
    public void setButtonText(int btnIndex, int value) {
        switch (btnIndex) {
            case 1:
                btnCounter1.setText("Количество = " + value);
                break;
            case 2:
                btnCounter2.setText("Количество = " + value);
                break;
            case 3:
                btnCounter3.setText("Количество = " + value);
                break;
        }
    }
}

<TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:text="@string/_1" />

    <Button
        android:id="@+id/btnCounter1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Количество = 0" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="8dp"
        android:layout_marginTop="8dp"
        android:text="@string/_2" />

    <Button
        android:id="@+id/btnCounter2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Количество = 0" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="8dp"
        android:layout_marginTop="8dp"
        android:text="@string/_3" />

    <Button
        android:id="@+id/btnCounter3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Количество = 0" />
</LinearLayout>