4. Android NDK : Android Native Development Kit allows to develop part of applications in native code languages. It can be downloaded from https://developer.android.com/tools/sdk/ndk/index.html. It is mainly used if you want to reuse existing code libraries in these languages.
5. Xamarian for Visual Studio: This will allow development with Xamarin.Android in Visual Studio. It can be downloaded from Xamrian website. They provide 30 day free trial.
Once you start installing Xamrian it will check if all the components required are installed if not it will install.
After installation is complete Start Visual Studio go to Tools - > Option - > Xamarin - > Android Settings to check if all the required tools are installed and detected correctly.
5. Developing Android Application
A simple application which takes an input(name) from user and displays a welcome message.
1. Start Visual Studio 2010 and create a new project
2. Select Blank App (Android). Give the application name "Hello World" and click Ok. Visual Studio will create a new project as shown below