Start this course: https://www.udacity.com/course/android-development-for-beginners--ud837

Finish Lesson 1A. Feel free to skip Introduction, Preparing for the Journey Ahead, and Talking to Your Phone.

Note: The course uses an XML visualizer for the exercises. Since we've already started poking around in Android Studio, you have a choice. Either:

• Use the XML visualizer for the exercises, or
• Use Android Studio.

If you are using Android Studio, you have to make a small change to their code examples. You need to add the following attribute: xmlns:android="http://schemas.android.com/apk/res/android". For example, if the example is:

<TextView
    android:text="Hello World!"
    android:layout_width="100dp"
    android:layout_height="100dp"
    android:id="@+id/textView" />

you need to add in the extra attribute to make it:

<TextView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:text="Hello World!"
    android:layout_width="100dp"
    android:layout_height="100dp"
    android:id="@+id/textView" />

This xmlns attribute is explained in a later lesson.