Once you've installed everything you need to develop an Android application, you'll want to figure out how to actually run the code you're going to write. One option is to plug in your phone or pad and run it just by clicking the run button in Eclipse. But if you want to simulate testing your code on different platforms or run your code without pluging in an external device, you'll need to set up an emulator. Fortunately the Android SDK makes it easy to do just that.
I'll be releasing a handful of free videos from the complete course - enough to get you started - and you can find the complete course right here.