install the JDK, if you don't have it already.
Step 2. Downloading the SDK Starter PackageThe SDK starter package is not a full development environment—it includes only the core SDK Tools, which you can use to download the rest of the SDK components (such as the latest Android platform).
Step 3. Installing the ADT Plugin for Eclipse
Step 4. Adding Platforms and Other ComponentsThe SDK uses a modular structure that separates the major parts of the SDK—Android platform versions, add-ons, tools, samples, and documentation—into a set of separately installable components. The SDK starter package, which you've already downloaded, includes only a single component: the latest version of the SDK Tools. To develop an Android application, you also need to download at least one Android platform and the associated platform tools. You can add other components and platforms as well, which is highly recommended.
If you used the Windows installer, when you complete the installation wizard, it will launch the Android SDK and AVD Manager with a default set of platforms and other components selected for you to install. Simply click Install to accept the recommended set of components and install them. You can then skip to Step 5, but we recommend you first read the section about the Available Components to better understand the components available from the Android SDK and AVD Manager.