How to make the main activity, at startup, show a fragment?

Question

Android

Good
for the second day, I’m fighting, I can’t understand, there is an activity, there are fragments in it, there is a menu, with the help of it all the fragments switch normally, but I need it to show the first fragment at startup, but alas ..

import android.content.Intent;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import www.finefood.CreateNewUser.CreateNewUser;
import www.finefood.R;
import www.finefood.TestData.TestData;
import www.finefood.main.Fragment.AbstractionFragment;
import www.finefood.main.Fragment.CreateMenuFragment;
import www.finefood.main.Fragment.SettingMenuFragment;
import www.finefood.main.Fragment.WatchProgressFragment;

public class MainActivity extends AppCompatActivity {

    private String[] titles;
    private ListView drawerList;

    FragmentTransaction transaction;
    FragmentManager manager;

    AbstractionFragment createMenuFragment = new CreateMenuFragment();
    AbstractionFragment watchProgressFragment = new WatchProgressFragment();
    SettingMenuFragment settingMenuFragment = new SettingMenuFragment();

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.main_layout);

        titles = getResources().getStringArray(R.array.menu_fragment);
        drawerList = (ListView) findViewById(R.id.drawer);
        drawerList.setAdapter(new CustomListAdapter(this,
                android.R.layout.simple_list_item_1, titles));
        drawerList.setOnItemClickListener(new DrawerItemClickListener());
    }

    @Override
    protected void onStart() {
        super.onStart();
        //Заплатака
        if (!TestData.testNewUser)
        //Заплатка
        {
            Intent intent = new Intent(getApplicationContext(), CreateNewUser.class);
            startActivity(intent);
            this.finish();
        }
        manager = getSupportFragmentManager();
        transaction = manager.beginTransaction();
        transaction.add(R.id.drawer_container, createMenuFragment, createMenuFragment.getTitle());
    }

    /*
    * приватный класс, выводит необходимый фрагмент в MainActivity по нажатию меню.
    * Возможно стоит вынести отдельно, но в конструктор нужно передать ссылку на FragmentActivity
    */


    private class DrawerItemClickListener implements ListView.OnItemClickListener {

        @Override
        public void onItemClick(AdapterView<?> adapterView, View view, int position, long id) {
            manager = getSupportFragmentManager();
            transaction = manager.beginTransaction();
            switch (position) {
                case 0:
                    if (manager.findFragmentByTag("CreateMenuFragment") == null)
                        transaction.replace(R.id.drawer_container, createMenuFragment, createMenuFragment.getTitle());
                    break;
                case 1:
                    if (manager.findFragmentByTag("WatchProgressFragment") == null)
                        transaction.replace(R.id.drawer_container, watchProgressFragment, watchProgressFragment.getTitle());
                    break;
                case 2:
                    if (manager.findFragmentByTag("SettingMenuFragment") == null)
                        transaction.replace(R.id.drawer_container, settingMenuFragment, settingMenuFragment.getTitle());
                    break;
            }

            transaction.commit();
        }
    }
}

the layout itself

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@color/colorStage"
        android:id="@+id/drawer_layout">

    <android.support.v4.widget.DrawerLayout

            android:id="@+id/drawer_container"
            android:layout_width="match_parent"
            android:layout_height="match_parent">
    </android.support.v4.widget.DrawerLayout>

    <ListView
            android:id="@+id/drawer"
            android:dividerHeight="5dp"
            android:background="@color/listViewBackground"
            android:choiceMode="singleChoice"
            android:layout_gravity="start"
            android:layout_width="300dp"
            android:layout_height="match_parent">
    </ListView>
</android.support.v4.widget.DrawerLayout>