I'm working through the android tutorial at
<http://developer.android.com/training/basics/firstapp/building-ui.html>

I've created the project as stated in the tutorial however the code that it says is supposed to be in my activity.xml file is instead in my content.xml file its as if they have swapped?

Code in activity xml:

```
    <?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:fitsSystemWindows="true"
tools:context=".MyActivity">

<android.support.design.widget.AppBarLayout android:layout_height="wrap_content"
    android:layout_width="match_parent" android:theme="@style/AppTheme.AppBarOverlay">

    <android.support.v7.widget.Toolbar android:id="@+id/toolbar"
        android:layout_width="match_parent" android:layout_height="?attr/actionBarSize"
        android:background="?attr/colorPrimary" app:popupTheme="@style/AppTheme.PopupOverlay" />

</android.support.design.widget.AppBarLayout>

<include layout="@layout/content_my" />

<android.support.design.widget.FloatingActionButton android:id="@+id/fab"
    android:layout_width="wrap_content" android:layout_height="wrap_content"
    android:layout_gravity="bottom|end" android:layout_margin="@dimen/fab_margin"
    android:src="@android:drawable/ic_dialog_email" />

</android.support.design.widget.CoordinatorLayout>

```

Code in content xml:

```
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:showIn="@layout/activity_main" tools:context=".MainActivity">

<TextView android:text="Hello World!" android:layout_width="wrap_content"
    android:layout_height="wrap_content" />
</RelativeLayout>

```

The tutorial is telling me to change the relative layout block to linear layout (which it says should be in the activity xml, but for me its in content xml)

So when I replace the code in activity xml with what the tutorial has it gives me errors because I removed the code that was there previously.

OR 

if I edit the code in content xml and run the app I can't see the changes because activity is not updated, and I cant move the linear layout code to activity xml because it gives me "multiple root tags" error.

Can someone show me a solution that will allow me to continue with the tutorial, because if I edit the java code or something like that I get problems with later stages in the tutorial.

Thanks