Android is the world's most-used mobile operating system. As an Android developer you write apps (in Kotlin or Java) that run on phones, tablets, TVs and watches. In this first topic you'll set up everything and run an app — no prior experience needed.

What you actually build with

You write your app in Kotlin (the modern, recommended language), design screens with XML layouts or Jetpack Compose, and the build tool Gradle packages everything into an installable .apk / .aab file.

Step 1 — Install Android Studio

Android Studio is the official IDE (the program you code in). It bundles the code editor, the Android SDK, an emulator (a virtual phone), and the build tools.

• Download it from developer.android.com/studio.
• During first launch it downloads the SDK (Software Development Kit) — let it finish.
• Create a virtual device (AVD) from Device Manager, e.g. a Pixel running the latest Android.

Step 2 — Create your first project

Choose New Project → Empty Activity, pick a name, set the language to Kotlin, and a minimum SDK (API 24 is a safe choice — it reaches ~95% of devices).

Step 3 — Run it

Press the green ▶ Run button. Android Studio builds the app and installs it on your emulator or a real phone (with USB debugging enabled). You'll see "Hello Android".

// MainActivity.kt — the entry screen of the app
class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main) // show this layout
    }
}

Summary

You installed Android Studio, learned the pieces (Kotlin, layouts, Gradle, SDK, emulator), and ran your first app. Next we'll learn the Kotlin language you'll write everything in.