Content.xml and List Views

I have been doing this course on making the stormy application with the newest Android Studio version, and I was a little confused because my Activity.xml wasn't working. I figured out I was supposed to use the Content.xml so I have been using that. Am I really supposed to use the Content.xml layout?

I started the part 2 for the stormy course. Everything has been working fine until I came upon the List Views. First of all, I made the new activity. In the content_daily_forecast.xml, I had a little (I think it's called floatingActionButton) button which I could not delete. Furthermore after I made the new activity, inside the DailyForecastActivity.java, I had to change: "public class DailyForecastActivity extends AppCompatActivity {..........}" to "public class DailyForecastActivity extends ListActivity {.........}" and some code was marked with an error.

This is my code and the information which I will mark in between two !!!!! is where the errors are:

public class DailyForecastActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_daily_forecast);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        !!!!! setSupportActionBar !!!!! (toolbar);

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });
        !!!!! getSupportActionBar !!!!! ().setDisplayHomeAsUpEnabled(true);
    } 
}

Can someone help me fix these errors and also to delete that little round "floatingActionButton"?

Thank you!